Soda-lime glasses hardness

Chemical Characteristics. The most common type of glass is known as soda-lime glass and is made primarily of silica (60 to 75 percent). Sodium carbonate, or soda ash, is added to the silica to lower its melting point. Because the presence of soda ash makes it possible for water to dissolve glass, a third compound such as calcium carbonate, or limestone, must be added to increase insolubility and hardness. For some types of glass, compounds such as lead oxide or boric oxide are added to enhance properties such as brilliance and resistance to heat. 

For the determination of scratch hardness of soda-lime glass(Matsunami 0050), a normal load and a scratch speed were fixed at 0.98 N and 0.05 mm/s, respectively. Water and some n-alcohols(l-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, 1-decanol, and 1-undecanol) were employed as environment. These liquids except for... 

Figure 3 shows scratch hardness of soda-lime glass in water and in n-alcohols. Scratch hardness increases with an increase in the number of carbon atoms in each alcohol molecule, but shows a maximum at 1-decanol. Scratch hardness obtained in 1-decanol is 28% larger than that in 1-pentanol. Scratch hardness obtained in water is comparable with that in 1-pentanol. 

Figure 3. Scratch hardness of soda lime glass in water and n alcohols. Error bars indicate 1 standard deviations.

The crack initiation load of silica glass is much lower than those of Tempax and soda-lime glasses (Table 1). This lower crack initiation load cannot be explained in terms of conventional mechanical properties, e.g. Young s modulus and fracture toughness. Table 3 shows some mechanical properties of silica, Tempax, and soda-lime glasses. Here, Young s modulus and Vickers hardness are the catalogue values. 

Due to the presence of glass in the composite samples prepared with the use of sodium bisulfite-soda lime glass system, their hardness was superior to those of the corresponding samples obtained... 

Contains Nitrogen.—First test the original solid ni liquid by heating in a hard-glass tube with soda-lime (p. 2), and notice if the smell is that of ammonia (ammonia salt, amide or cyanide), an amine (amine or amino-acid) or a pyridine base (alkaloid). 

For the hard borosilicate glasses and the soda-lime-silica glasses this if around 0-0025 cal °C" cm sec. For vitreous silica (Vitreosil) in the transparent form it is 0-0025 up to 500°C, and 0-0035 from 500 to 1000°C for the translucent form it is 0-0033. 

VII. Heat with Soda-lime.—Grind about 0-5 gm. with 2 gms. soda-lime in a mortar. Transfer to small hard glass tube, cover with a layer of ground soda-lime and heat. Detect odour and inflammability of any gases evolved. 

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