| 摘要 |
PROBLEM TO BE SOLVED: To provide a quartz article the surface of which is subjected to sand blasting and in which particles can be prevented from being generated from the sand-blasted surface. SOLUTION: In this quartz article which has a sand-blasted surface and is manufactured by cleaning the sand-blasted surface, the numbers of four kinds of particles, namely, particles having 0.2-0.3μm (excluding 0.3μm) particle size, particles having 0.3-0.5μm (excluding 0.5μm) particle size, particles having 0.5-1.0μm (excluding 1.0μm) and particles having >=1.0μm particle size, all of which particles are generated from the sand-blasted surface of the quartz article by blowing clean air on the surface, are adjusted to <=30, <=60, <=60 and <=10 [per CF (cubic foot) of ambient air] respectively.
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