Abstract The present invention is directed to the production of glass-ceramic coatings capable of being fired repeatedly to temperatures in excess of 950° C. without thermal deformation and being especially suitable for application to titanium-stabilized stainless steels. The coatings are highly crystalline, substantially free from alkali metal oxides, and consist essentially, by weight, of: ______________________________________ MgO 5-35
CaO 0-35
ZnO 0-25
CaO + ZnO 10-35
Al 2 O 3 0-10
B 2 O 3 0-25
P 2 O 5 0-10
B 2 O 3 +
P 2 O 5 4-25
SiO 2 25-50
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Glass-ceramic coating compositions capable of being fired repeatedly to temperatures greater than 950° C. without undergoing thermal deformation, exhibiting coefficients of thermal expansion (25°-600° C.) between about 80-125×10 -7 /° C., and being substantially free from alkali metal oxides consisting essentially, expressed in terms of weight percent on the oxide basis, of: ______________________________________
MgO 5-35
CaO 0-35
ZnO 0-25
CaO + ZnO 10-35
Al.sub.2 O.sub.3
0-10
B.sub.2 O.sub.3
0-25
P.sub.2 O.sub.5
0-10
B.sub.2 O.sub.3 +
P.sub.2 O.sub.5
4-25
SiO.sub.2
25-50
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Claim 2
Dependent Claim
81 words
Glass-ceramic coating compositions capable of being fired repeatedly to temperatures greater than 950° C. without undergoing thermal deformation, exhibiting coefficients of thermal expansion (25°-600° C.) between about 80-125×10 -7 /° C., and being substantially free from alkali metal oxides consisting essentially, expressed in terms of weight percent on the oxide basis, of: ______________________________________
MgO 5-35
CaO 0-35
ZnO 0-25
CaO + ZnO 10-35
Al.sub.2 O.sub.3
0-10
B.sub.2 O.sub.3
0-25
P.sub.2 O.sub.5
0-10
B.sub.2 O.sub.3 +
P.sub.2 O.sub.5
4-25
SiO.sub.2
25-50
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Claim 3
Dependent Claim
29 words
Glass-ceramic coating compositions according to claim 1 consisting essentially of: ______________________________________
MgO 5-25
CaO 15-35
Al.sub.2 O.sub.3
0-10
B.sub.2 O.sub.3
6-25
ZnO 0-15
P.sub.2 O.sub.5
0-10
SiO.sub.2
30-50
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