Microhardness of Glass

McKinney, J. E., Antonucci, J. M. Rupp, N. W. (1987). Wear and microhardness of glass-ionomer cement. Journal of Dental Research, 66, 134-9. 

M. Prod homme, Some Results Concerning the Microhardness of Glasses, Phys. Chem. Glasses, 9 (3), 101 (1968). 

P.R. Perondi, P.H.C. Oliveira, A. Cassoni, A.F. Reis, J.A. Rodrigues, Ultimate tensile strength and microhardness of glass ionomer materials, Braz. Dent Sci. 17 (2014) 16-22. 

G. H. Frischat, Load Independent Microhardness of Glasses, in Strength of Inorganic Glasses, ed. C. R. Kurkjian, (Plenum Press, NY, 1986), pp. 135 145. 

Polish rate vs. Vickors microhardness of various glasses listed in Table 5.1. (From Ref. (3).)... 

The advantage of the modified additivity law incorporating Tg (eq. (5.17)), is that it is possible to use it to account for the contribution of any amorphous phase and/or component to the overall microhardness of the system, provided the Tg of this phase and/or component is known. Hence, for systems which contain more than one crystalline and/or amorphous phases with glass transition temperamres and mass fractions Tgi and Wi, respectively, the additivity law can be presented in the following way ... 

Mishra et al. [1994] and Bajpai et al. [1994] determined the microhardness of PMMA/PVDF and PMMA/PCTFE blends (Table 11.9) made by solution casting from dimethyl formamide solutions. The solutions containing the two polymers were heated at 110°C for 3 h and were poured into an optically plain glass mold to prepare pellets of the blends. The poured material was annealed at 75°C for 3 h. The samples were cut from the slowly cooled (24 h) pellets for this work. 

A calculation of the value of AH = AH/n per chemical bond did not give such good results as for Tp E, F and large fluctuations in the value of AH for these materials were obtained. This is evidently connected with a specific feature of the method since Myuller has shown [11] that measurements of the microhardness of different glasses result in the breaking of a different fraction of the chemical bonds in each individual case. Only a qualitative correlation is therefore possible. 

Figure 6. Modulus and microhardness of Sialon or oxynitride fibers versus nitrogen content. Redrawn from J. Kobayashi, M. Oota, K. Kada and H. Minakuchi, Oxynitride Glass and the Fiber Thereof, US Patent 4,957,883, September 18,1990.

Haile JM (1992) Molectrlar dynamics simrrlation elementary methods. John Wiley Sons, Inc., New York Hetherington G, Jack K, Kermedy J (1964) The viscosity of vitreous silica. Phys Chem Glasses 5 130-136 Hirao K, Tomozawa M (1987) Microhardness of Si02 Glass in various envirorunents. J Am Ceram Soc 70 497-502... 

The microhardness of glassy polymers decreases with increasing temperature because of thermal expansion (9). At the glass-transition temperature Tg, the onset of liquid-like motions takes place. The motions of long segments above Tg require more free volume and lead to a fast decrease of microhardness with temperature. The microhardness of several glassy polymers, measured at room temperature, has been shown to be directly proportional to its glass-transition temperature (10). 

K. Hirao and M. Tomozawa, Microhardness of Si02 glass in various environments, J. Am. Ceram. 

Sanditov, D. S., Sangadiev, S. Sh. (1988). About Internal Pressure and Microhardness of Inorganic Glasses. Fizika i Khimiya Stekla, 24(6), 741-751. 

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