Hirdetés

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  • Aladdin

    senior tag

    válasz Balli #351 üzenetére

    ''Sapphire glass characteristic

    The hardness of sapphire is extremely high which is scale 9 of moh's scale, only second to diamond. This also explains why watch crystals made of sapphire have a very good mechanical strength, wear and weather resistance. Sapphire is commonly used in high — class watches.

    Sapphire is chemically very stable, insoluble in watch, resistant to acids and alkaline. Sapphire only reacts with hydrofluoric acid, phosphoric acid and potassium hydroxide at high temperature of above 300 degree celsius. Sapphire has over 95% light transmission rate on natural light ray and over 85% on infrared ray. Because of its excellent transmission for infrared ray, sapphire is also widely used as infrared filters in military and industrial applications.''

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