234 results match your criteria micro-hardness surface

Study on laser powder bed fusion of nickel-base alloy of G-surface structure: scanning strategy, properties and compression properties.

Sci Rep 2021 Mar 25;11(1):6947. Epub 2021 Mar 25.

School of Mechanical, Materials, Mechatronic and Biomedical Engineering, University of Wollongong, Wollongong, Australia.

Aiming at laser powder bed fusion of GH3536 nickel base alloy, the effects of different scanning strategies on microstructure, porosity and mechanical properties were explored. In the aspect of microstructure and micro hardness of the sample, three scanning strategies had little difference; in the aspect of macro mechanical properties of the sample, the slope subarea scanning was better than the helix and island scanning. On this basis, the slope subarea scanning was selected as the optimal scanning strategy to form the G-surface structure, and the compression performance of G-surface was studied. Read More

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Biological and Mechanical Properties of Denture Base Material as a Vehicle for Novel Hydroxyapatite Nanoparticles Loaded with Drug.

Adv Pharm Bull 2021 Jan 7;11(1):86-95. Epub 2020 Nov 7.

Fixed and Removable Prosthodontics Department, National Research Centre, 33 El Buhouth Street, Dokki, P.O.12622 Cairo, Egypt.

This study aimed to evaluate the biological and mechanical properties of the poly(methyl methacrylate) (PMMA) denture base material as a vehicle incorporating novel hydroxyapatite nanoparticles (HA-NP) loaded with metronidazole (MZ) drug. HA-NP was prepared via wet-chemical-method, characterized by XRD, SEM/EDX, TEM, Fourier-transform infrared spectroscopy (FTIR), as well as the measurement of surface area and pore-size distribution. Four drug delivery formulas were prepared in the form of discs (10 x 2 mm) as follows: F1 (MZ/ HA-NP/PMMA), F2 (HA-NP/ PMMA), F3 (control-PMMA) and F4 (MZ/PMMA). Read More

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January 2021

Use of a novel 9.3-μm carbon dioxide laser and silver diamine fluoride: Prevention of enamel demineralisation and inhibition of cariogenic bacteria.

Dent Mater 2021 Mar 8. Epub 2021 Mar 8.

Faculty of Dentistry, The University of Hong Kong, Hong Kong 999077, China. Electronic address:

Objective: To investigate the effects of a 9.3-μm carbon dioxide (CO) laser and silver diamine fluoride (SDF) on the prevention of enamel demineralisation and inhibition of cariogenic bacteria.

Methods: Enamel blocks were applied with Laser (Group-1), SDF (Group-2), Laser + SDF (Group-3) and no treatment (Group-4), and then subjected to an 8-day pH-cycling for cariogenic challenge. Read More

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Effect of deep rolling on subsurface conditions of CoCr28Mo6 wrought alloy to improve the wear resistance of endoprostheses.

J Mech Behav Biomed Mater 2021 Feb 25;118:104398. Epub 2021 Feb 25.

Institute of Materials and Joining Technology, Otto-von-Guericke University Magdeburg, Germany.

Wear of orthopaedic endoprostheses is associated with adverse local and systemic reactions and can lead to early implant failure. Manufacturing determines the initial subsurface microstructure of an alloy that influences the implant's wear behaviour. Therefore, this study aims at generating enhanced wear resistances by a modification of the surface and subsurface microstructure of a CoCr28Mo6 wrought alloy by applying deep rolling. Read More

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February 2021

Ultrasonic Deposition of Carbon Nanotubes on Polycrystalline Cubic Boron Nitride Composites.

Materials (Basel) 2021 Jan 21;14(3). Epub 2021 Jan 21.

Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, 70125 Bari, Italy.

Polycrystalline cubic boron nitride (PcBN) are super-hard materials with high hardness and excellent abrasive resistance, widely used in cutting tools for precision machining of automotive and aerospace parts; however, their brittle properties make them prone to premature failure. Coatings are often applied to PcBN to extend their range of applicability and durability. Conventional coating methods are limited to the thickness range of a few hundred nanometres, poor adhesion to the substrate, and limited stability under ambient conditions. Read More

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January 2021

Evaluation of the remineralisation potential of bioactive glass, nanohydroxyapatite and casein phosphopeptide-amorphous calcium phosphate fluoride-based toothpastes on enamel erosion lesion -An study.

Indian J Dent Res 2020 Sep-Oct;31(5):670-677

Department of Conservative Dentistry and Endodontics, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, JSS Medical Institutions Campus, Sri Shivarathreeshwara Nagar, Mysuru, Karnataka, India.

Background: Erosion, a dynamic process with periods of demineralisation and remineralisation, has become a common problem in modern societies, owing to changes in life style and dietary habits. Although fluorides have been included in toothpastes that claim to prevent demineralisation and aid remineralisation, their ability to remineralise is limited by low concentration of calcium and phosphate ions available in saliva. Hence, a new paste based on casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), nanohydroxyapatite and bioactive glass (BAG) were introduced. Read More

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January 2021

Li-doped bioglass® 45S5 for potential treatment of prevalent oral diseases.

J Dent 2021 Feb 29;105:103575. Epub 2020 Dec 29.

Faculty of Dentistry, University of Chile, Santiago, Chile. Electronic address:

Objectives: Despite the excellent properties of both pure bioglasses (BG) and BG doped with therapeutic ions (such as Li) in hard tissue applications, there is not enough information about their role in the remineralization and bacterial-growth in oral diseases. The aim of this contribution is to evaluate the effect of both pure BG and BG doped with 5-wt% of Li (BGLi) on both the remineralization of in vitro demineralized human-teeth and the antimicrobial behavior against strains from caries and periodontitis.

Methods: Bioglass® 45S5 (BG) and BGLi were synthesized by the sol-gel method. Read More

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February 2021

Linear-nonlinear optical and quantum chemical studies on Quinolinium 3,5-dinitrobenzoate: A novel third order non-linear optical material for optoelectronic applications.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Mar 11;249:119304. Epub 2020 Dec 11.

Department of Physics, Nehru Arts and Science College, Kanhangad 671314, Kerala, India. Electronic address:

An organic non-linear optical (NLO) crystal of Quinolinium 3,5-dinitrobenzoate (DNBAQ) was synthesized and good quality single crystals of DNBAQ were grown by conventional slow evaporation solution growth technique. Single crystal XRD was utilized to confirm the formation of the charge transfer complex. The crystalline property and the presence of required functional groups was verified employing Powder XRD and FTIR spectral analysis. Read More

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Could sonic delivery of bulk-fill resins improve the bond strength and cure depth in extended size class I cavities?

J Clin Exp Dent 2020 Dec 1;12(12):e1131-e1138. Epub 2020 Dec 1.

DDS, MSc, PhD student, Department of Dentistry, Federal University of Maranhão (UFMA), São Luís, Maranhão, Brazil.

Background: The implementation of restorative procedures that guarantee success and optimize clinical time is the target of investigations in Restorative Dentistry. This study aimed to analyze the influence of sonic insertion of bulk-fill (BF) and conventional (C) resin composites on the microtensile bond-strength (µ-TBS) and cure depth (CD) of large and deep class I restorations.

Material And Methods: Fifty-six healthy human premolars were selected and occlusal cavities (4 x 4 x 3 mm; factor C = 5) were prepared. Read More

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December 2020

Time-dependent Microhardness Gradients of Self-adhesive Resin Cements Under Dual- and Self-curing Modes.

Oper Dent 2020 Nov;45(6):E280-E288

Clinical Relevance: Acid-functional monomers in self-adhesive resin cements may decrease their self-curing polymerization ability. Light irradiation optimizes polymerization performance.

Summary: Purpose: The aim of this study was to investigate Knoop microhardness of self-adhesive resin cements under dual- and self-curing modes in simulated canals for describing the polymerization behavior. Read More

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November 2020

Preparation of a toothpaste containing theobromine and fluoridated bioactive glass and its effect on surface micro-hardness and roughness of enamel.

Dent Mater J 2021 Mar 19;40(2):393-398. Epub 2020 Nov 19.

Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University.

The aim was to synthesize a toothpaste and analyze its effect on surface micro-hardness and roughness of enamel. Basic paste was prepared by using basic ingredients. Theobromine (0. Read More

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Qualitative and quantitative assessment of the potential effect of cigarette smoking on enamel of human smokers' teeth.

Arch Oral Biol 2021 Jan 21;121:104953. Epub 2020 Oct 21.

Faculty of Dentistry, Tanta University, El-Giesh St., Tanta, Gharbia, Egypt. Electronic address:

Objective: This study aimed to examine the potential changes in enamel surface of human smokers' teeth.

Materials And Methods: Forty extracted permanent, human, noncarious anterior teeth were used in this study. Half of these teeth were obtained from heavy smokers, while the other half of teeth were collected from nonsmokers (control teeth). Read More

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January 2021

The impact of different low-pressure plasma types on the physical, chemical and biological surface properties of PEEK.

Dent Mater 2021 Jan 2;37(1):e15-e22. Epub 2020 Nov 2.

Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Dental Materials and Biomaterial Research, Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Aßmannshauser Str. 4-6, 14197 Berlin, Germany. Electronic address:

Objective: Plasma treatment can be used as surface treatment of PEEK (poly-ether-ether-ketone) to increase the bonding strength between veneering composite and dental prosthetic frameworks of PEEK or enhance biocompatibility of PEEK implants. These improvements are probably based on chemical changes of the PEEK surface. However, the aim of the study was to evaluate the impact of different low-pressure plasma treatments on surface properties of PEEK, such as roughness, hydrophilicity, micro-hardness, crystallinity and biological activity of PEEK. Read More

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January 2021

Two-in-one strategy: a remineralizing and anti-adhesive coating against demineralized enamel.

Int J Oral Sci 2020 09 29;12(1):27. Epub 2020 Sep 29.

State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.

Tooth enamel is prone to be attacked by injurious factors, leading to a de/remineralization imbalance. To repair demineralized enamel and prevent pulp inflammation caused by biofilm accumulation, measures are needed to promote remineralization and inhibit bacterial adhesion on the tooth surface. An innovative material, poly (aspartic acid)-polyethylene glycol (PASP-PEG), was designed and synthesized to construct a mineralizing and anti-adhesive surface that could be applied to repair demineralized enamel. Read More

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September 2020

Comparative Quality Control of Titanium Alloy Ti-6Al-4V, 17-4 PH Stainless Steel, and Aluminum Alloy 4047 Either Manufactured or Repaired by Laser Engineered Net Shaping (LENS).

Materials (Basel) 2020 Sep 19;13(18). Epub 2020 Sep 19.

Materials Science and Engineering Division, Depot 22, Israel Air Force, P.O. Box 02538, Tel Aviv, Israel.

Additive manufacturing attracts much interest for manufacturing and repair of structural parts for the aerospace industry. This paper presents comparative characterization of aircraft items made of Al 4047 alloy, Ti-6Al-4V alloy, and 17-4 precipitation hardened (PH) (AISI 630) stainless steel, either manufactured or repaired by laser engineered net shaping (LENS). Chemical analysis, density, and surface roughness measurements, X-ray micro-computed tomography (μ-CT) analysis, metallography, and micro-hardness testing were conducted. Read More

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September 2020

Changes in tribological and antibacterial properties of poly(methyl methacrylate)-based 3D-printed intra-oral appliances by incorporating nanodiamonds.

J Mech Behav Biomed Mater 2020 10 21;110:103992. Epub 2020 Jul 21.

Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea; BK21 PLUS Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea. Electronic address:

It is essential for 3D-printed intra-oral appliances to be able to withstand the mechanical and microbial insult existent in the harsh environment of the oral cavity. Poly(methyl methacrylate) (PMMA)-based appliances are widely used in dentistry. Hence, the present study aimed to evaluate the role of nanodiamonds (NDs) as fillers to enhance the resistance to friction and wear. Read More

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October 2020

Effects of Laser Shock Peening on Microstructure and Properties of Ti-6Al-4V Titanium Alloy Fabricated via Selective Laser Melting.

Materials (Basel) 2020 Jul 23;13(15). Epub 2020 Jul 23.

Key Laboratory for Microstructures, School of Materials Science and Engineering, Shanghai University, Shanghai 200444, China.

Laser shock peening (LSP) is an innovative surface treatment process with the potential to change surface microstructure and improve mechanical properties of additively manufactured (AM) parts. In this paper, the influences of LSP on the microstructure and properties of Ti-6Al-4V (Ti64) titanium alloy fabricated via selective laser melting (SLM), as an attractive AM method, were investigated. The microstructural evolution, residual stress distribution and mechanical properties of SLM-built Ti64 samples were characterized before and after LSP. Read More

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Dataset of wind blow sand erosion test on ultrasonic surface treated cementitious composites.

Y Shi Z M Shi

Data Brief 2020 Aug 27;31:105943. Epub 2020 Jun 27.

School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot, Inner Mongolia, PR China.

In this paper, we take cement mortar and paste as specimens, a novelty method named ultrasonic surface treatment(UST) was employed to form a hardening surface layer on cementitious specimens to improve its wind-blown sand erosion resistance, surface hardness and apparent density. The specimens with curing ages of 1-day, 3-days, 7-days, and 28-days were adopted. The wind blown sand erosion test was carried out in a wind-blown sand erosion test system, which simulated a wind blown sand environment of a wind speed of 30 m/s and a sand feed rate of 30 g/min. Read More

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Effect of time on the post-irradiation curing of six resin-based composites.

Dent Mater 2020 08 27;36(8):1019-1027. Epub 2020 Jun 27.

Dalhousie University, Faculty of Dentistry, Dental Clinical Sciences, Halifax, Nova Scotia, Canada. Electronic address:

Objectives: To evaluate the effect of time on the Vickers microhardness (VH) at the top and bottom surfaces of six conventional resin-based composites (RBCs) up to twelve weeks after light curing.

Methods: Five specimens of Filtek Supreme Ultra, Herculite Ultra, Mosaic Ultra, Tetric EvoCeram, TPH Spectra HV, and Venus Pearl were packed into opaque molds that were 2.3mm in diameter and 2. Read More

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Influence of ultrasonic excitation on microhardness of glass ionomer cement.

Technol Health Care 2020 ;28(6):587-592

Department of Restorative Dentistry and Endodontics, College of Dentistry, King Faisal University, Al Ahsa, Saudi Arabia.

Background: Numerous researchers have attempted to improve the mechanical properties of glass ionomer cement since 1972. In this study, ultrasonic curing treatment was introduced during the mixing of glass ionomer cement (GC Fuji IX) to facilitate intimate mixing, compaction and adaptation of residual glass particle which consequently improves densification of the material.

Objective: To assess the influence of ultrasonic treatment on the microhardness of glass ionomer cement (GC Fuji IX) and compare it with the conventionally cured method. Read More

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January 2020

Comparative evaluation of three different toothpastes on remineralization potential of initial enamel lesions: A scanning electron microscopic study.

Indian J Dent Res 2020 Mar-Apr;31(2):217-223

Department of Pediatric and Preventive Dentistry, Kannur Dental College, Kannur, Kerala, India.

Background: The early enamel lesions are reversible as it is a process involving mineral transactions between the teeth and saliva.

Aim: To evaluate the efficiency of three different tooth pastes on remineralization potential of initial enamel lesions using Vickers Micro hardness Test and Scanning electron microscopy.

Materials And Methods: Artificial carious lesions were prepared in human enamel with demineralizing solution. Read More

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Pre-heating time and exposure duration: Effects on post-irradiation properties of a thermo-viscous resin-composite.

Dent Mater 2020 06 5;36(6):787-793. Epub 2020 May 5.

Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK; Photon Science Institute, University of Manchester, Manchester, UK. Electronic address:

Objective: To evaluate the effects of pre-heating time and exposure duration on the degree of conversion (DC), maximum rate of polymerization (RP), polymerization shrinkage strain (PS) and surface micro-hardness (VHN) of Viscalor.

Methods: Viscalor syringes were pre-heated using a Caps Warmer (VOCO, Germany) in T3 mode (at 68°C) for 30s (T3-30s) and 3min (T3-3min) and then the composite paste was extruded into appropriately sized molds. Light irradiation was applied at zero distance from the upper surface with a LED-LCU of mean irradiance 1200mW/cm for either 20 or 40s. Read More

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Preparation of Zn doped mesoporous silica nanoparticles (Zn-MSNs) for the improvement of mechanical and antibacterial properties of dental resin composites.

Dent Mater 2020 06 27;36(6):794-807. Epub 2020 Apr 27.

Institute of New Carbon Materials, Taiyuan University of Technology, 79 West Yingze Road, Taiyuan 030024, China.

Objective: The purpose of this work was to explore the enhancement effect of zinc doped mesoporous silica nanoparticles (Zn-MSNs), which could form micromechanical interlocking with resin matrix and sustainably release Zn, on the mechanical and antibacterial properties of the dental resin composites.

Methods: Zn-MSNs were prepared by a sol-gel method, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N adsorption/desorption. The mechanical properties of the dental composites reinforced by Zn-MSNs were measured by a universal mechanical testing machine. Read More

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Enhancing the Surface Quality of Micro Titanium Alloy Specimen in WEDM Process by Adopting TGRA-Based Optimization.

Materials (Basel) 2020 Mar 21;13(6). Epub 2020 Mar 21.

Department of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia.

The surface measures of machined titanium alloys as dental materials can be enhanced by adopting a decision-making algorithm in the machining process. The surface quality is normally characterized by more than one quality parameter. Hence, it is very important to establish multi-criteria decision making to compute the optimal process factors. Read More

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New Resin-Based Bulk-Fill Composites: Evaluation of Micro-Hardness and Depth of Cure as Infection Risk Indexes.

Materials (Basel) 2020 Mar 13;13(6). Epub 2020 Mar 13.

Department of Clinical, Surgical, Diagnostic and Paediatric Sciences - Section of Dentistry, University of Pavia, Piazzale Golgi 2, 27100 Pavia, Italy.

The current study evaluated the Vickers hardness number (VHN) and hardness ratio of four bulk-fill composites (VisCalor bulk; Admira Fusion x-tra; x-tra fil; and GrandioSO x-tra-Voco, Cuxhaven, Germany) to assess the risk of bacterial colonization in comparison with standard composite materials. Thirty samples were prepared for each group. The VHN of both the external (top) and internal surface (bottom) was determined with a micro-hardness tester (200 g load for 15 s), and the hardness ratio was also calculated for each sample. Read More

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Effect of Two Methods of Remineralization and Resin Infiltration on Surface Hardness of Artificially Induced Enamel Lesions.

J Dent (Shiraz) 2020 Mar;21(1):12-17

Dental Research Center, Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran.

Statement Of The Problem: The progression of incipient carious lesions may be simply prevented by non-invasive remineralization of lesions, eliminating the need for invasive and high-cost restorative procedures.

Purpose: This study aimed to assess the effect of two commonly used remineralizing agents and resin infiltration on surface micro hardness of incipient enamel lesions at different time points.

Materials And Method: In this study, 45 intact human maxillary central incisors were selected. Read More

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Optimal Hot-Dipped Tinning Process Routine for the Fabrication of Solderable Sn Coatings on Circuit Lead Frames.

Materials (Basel) 2020 Mar 6;13(5). Epub 2020 Mar 6.

School of Environmental and Material Engineering, Yantai University, Yantai 264005, China.

Previous studies merely focus on the hot dipping properties of lead frame materials used in electronic industry. Yet, the environmentally friendly and cost-efficient traits of hot-dipped tinning process make it a possible promising surface modification technique compared with electroplating. As a result, the optimal hot-dipped tinning process routine is proposed in this paper. Read More

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Novel Confocal-Laser-Scanning-Microscopy and conventional measures investigating eroded dentine following dentifrice dab-on and brushing abrasion.

Heliyon 2020 Mar 2;6(3):e03282. Epub 2020 Mar 2.

School of Life Sciences, University of Dundee, UK.

Objectives: To validate novel non-contacting Confocal-Laser-Scanning-Microscopy (CLSM) methodology with conventional Contacting Profilometry (CP) measures investigating brushing or dab-on of stannous-fluoride dentifrice on early aggressive dentine erosion.

Methods: 75 polished human dentine samples were prepared and eroded in agitated 6% citric acid then randomly allocated into 5 intervention groups; artificial saliva control (1); controlled use of a pressure sensitive counter-rotating oscillatory powered toothbrush with sodium-fluoride NaF (2) or stannous-fluoride SnF (3), and dab-on application of NaF (4) or SnF (5). Samples underwent three cycles of intervention and 2-min agitated 6 % citric acid challenges. Read More

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Investigation of the effects of selected bio-based carburising agents on mechanical and microstructural characteristics of gray cast iron.

Heliyon 2020 Feb 22;6(2):e03418. Epub 2020 Feb 22.

Department of Chemical, Metallurgical and Materials Engineering, Tshwane University of Technology, Pretoria, South Africa.

The mechanism of graphite formation on gray cast iron metal during carburisation process using organic nano-carbon (ONC) was investigated at 900 °C for a holding time of three (3) hours. TEM and XRD were employed to characterize the pulverised nano-carbon to determine their phases and bonding potentials. Also, SEM/EDS, XRD and Vickers' hardness tester were employed to determine the microstructure, phase compositions as well as hardness and wear properties of the carburised material. Read More

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February 2020