| 摘要 |
For effective and easily workable protection such a method prevents formation of carbon oxide in the pores of the product by enveloping the outer faces of the product (3, 13) with air-tight shields (1, 2, 6; 12, 16, 17). This shield can be made either of a protective coating deposited on the outer faces of the product (3; 13) from the gaseous phase, or of steatite, porcelain, melted ceramic materials or metals (6; 16, 17). The shield can also be made of substances in melted condition, or as superficial layers of product impregnated with sealing compounds. Also the carbon oxide concentration in the pores of the product can be decreased by increased number of open pores in the product (3) enabling oxygen to penetrate to the pores and rarefy the carbon oxide atmosphere. Further formation of carbon oxide in the pores of the product (3) can be prevented by formation of a protective atmosphere (N2) in direct proximity to the outer faces of the product (3). |
