Resistance welding. Vickers hardness testing (low-force and microhardness) of resistance spot, projection, and seam welds

2011 ◽  
Keyword(s):  
Vickers Hardness ◽  
Resistance Welding ◽  
Hardness Testing ◽  
Resistance Spot

Substitution of Iron in Preparation of Enhanced Thermal Property and Bioactivity of Hydroxyapatite

2008 ◽  
Vol 55-57 ◽  
pp. 689-692 ◽  
Author(s):  
S. Meejoo ◽  
W. Pon-On ◽  
S. Charnchai ◽  
T. Amornsakchai
Keyword(s):  
Thermal Property ◽  
Vickers Hardness ◽  
Crystalline Phase ◽  
Vickers Microhardness ◽  
Experimental Methods ◽  
Hardness Testing ◽  
Thermal Behaviors ◽  
Carbonate Ions ◽  
Novel Material ◽  
Better Than

Incorporation of Iron into hydroxyapatite (HAp) has generated a novel material for which their properties differ from those of conventional HAp. Although XRD indicated that the as-prepared iron-substituted hydroxyapatite (HApFe) is of a single crystalline phase similar to that of HAp, we found that carbonate ions can incorporate in the HApFe structure 3 times better than in HAp. As results, HApFe possesses the Vickers microhardness about 1.5 times higher than that of HAp. Thermal behaviors and bioactivity of HApFe are discussed in comparison to those of HAp. Various experimental methods have been employed in this work including powder XRD, IR, SEM, DSC/TGA and Vickers Hardness testing.

scholarly journals Comparison of Hardness and Surface Roughness of Two Denture bases Polymerized by Different Methods

2012 ◽  
Vol 3 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Farideh Bahrani ◽  
Mahroo Vojdani ◽  
Anahita Safari ◽  
Ghasem Karampoor
Keyword(s):  
Mechanical Property ◽  
Surface Roughness ◽  
Injection Molding ◽  
Vickers Hardness ◽  
T Test ◽  
Hardness Testing ◽  
Denture Base ◽  
Hardness Tester ◽  
Base Materials ◽  
Acrylic Resins

ABSTRACT Purpose The aim of this study was to evaluate mechanical property hardness and surface roughness (Ra) of different polymerization acrylic resins used for denture bases. Materials and methods A total of 30 specimens were prepared and divided in two groups. A total of 15 samples were processed by the compression molding technique using Meliodent (heatcured). Another 15 samples were processed with cold-cured resin Futura Gen via the injection molding technique. Hardness testing was conducted using a Vickers hardness tester. The Ra test was performed by a profilometer. Data were analyzed using the independent sample t-test and differences were statistically significant at the 0.05 level. Results The Vickers hardness numbers (VHN) were 20.8 ± 2.39 for Meliodent and 21.18 ± 1.42 for FuturaGen, which was not significantly different (p > 0.05). The Ra of Meliodent was 0.92 ± 0.23 µm and for FuturaGen it was 0.84 ± 0.37 µm. There were no significant changes in roughness. Conclusion The hardness and Ra of Meliodent and FuturaGen were not significantly different. Therefore, we recommend the use of FuturaGen for manufacturing denture base materials. How to cite this article Bahrani F, Safari A, Vojdani M, Karampoor G. Comparison of Hardness and Surface Roughness of Two Denture bases Polymerized by Different Methods. World J Dent 2012;3(2):171-175.

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