Process for making a high temperature-resistant ceramic material with an adjustable thermal expansion coefficient and method of use of same

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—Al2O3 system with a predetermined thermal expansion behavior, said process comprising the steps of:

• a) burning a mixture containing a predetermined amount of magnesium aluminate (MgAl2O4) of a predetermined grain size distribution in a range of from 1 to 70 parts by weight with magnesium oxide (MgO) in an excess amount in another different predetermined grain size distribution large enough so that no added magnesium oxide is required so as to obtain a product having a thermal expansion coefficient (α), 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;
• and
• b) selecting said predetermined amount of said magnesium aluminate and said excess amount of said magnesium oxide ingredients 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 9×10−6 K−1 to 15×10−6 K−1.

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—Al2O3 system with a predetermined thermal expansion behavior, said process comprising the steps of:

• a) burning a mixture consisting of 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, a predetermined amount of magnesium aluminate (MgAl2O4) of another different predetermined grain size distribution in an amount range of from 1 to 70 parts by weight, a predetermined amount of from 1.5 to 7 parts by weight of calcium alumina cement, a predetermined amount of from 2 to 8 parts by weight of microsilica and a predetermined amount of from 1 to 10 parts by weight of water to obtain a product having a thermal expansion coefficient (α), 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;
• and
• b) selecting said predetermined amount 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 9×10−6 K−1 to 15×10−1 K−1.

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—Al2O3 system with a predetermined thermal expansion behavior, said process comprising the steps of:

• a) compressing a mixture consisting of 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, a predetermined amount of magnesium aluminate (MgAl2O4) of another different predetermined grain size distribution in an amount range of from 1 to 70 parts by weight, a predetermined amount of up to 20 parts by weight of at least one of an organic press-assisting agent and a binder and a predetermined amount of from 1 to 10 parts by weight of said water in a press to form a compressed mixture, 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;
• b) burning said compressed mixture to obtain a product having a thermal expansion coefficient (α);
• and
• c) selecting said predetermined amount 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 9×10−6 K−1 to 15×10−6 K−1.