Patent ID: 6274525
Filing Date: 2001-08-14
Classification: C03B,C04B

Abstract:
A process for making a high temperature-resistant ceramic material for a component, said component comprising platinum or a platinum alloy in contact with the high temperature-resistant ceramic material and said high temperature ceramic material comprising a MgO--Al.sub.2 O.sub.3 system with a predetermined thermal expansion behavior, said process comprising the steps of:a) burning a mixture containing a predetermined amount of magnesium oxide (MgO) of a predetermined grain size distribution in an amount range of from 30 to 99 parts by weight and a predetermined amount of magnesium aluminate (MgAl.sub.2 O.sub.4) of another different predetermined grain size distribution in an amount range of from 1 to 70 parts by weight to obtain a product having a thermal expansion coefficient (.alpha.), wherein said predetermined grain size distribution and said another different predetermined grain size distribution consist of respective grain size fractions, said respective grain size fractions including a <0.1 mm grain size fraction, a 0 to 1 mm grain size fraction and a 1 to 5 mm grain size fraction; andb) selecting said predetermined amounts of said magnesium oxide and said magnesium aluminate as well as said predetermined grain size distributions so that said thermal expansion coefficient of said product is substantially equal to that of said platinum or said platinum alloy and in a range of from 9.times.10.sup.-6 K.sup.1 to 15.times.10.sup.-6 K.sup.-1.