초록 ▼

This process serves to form a long-time-vacuum-tight, high-strength, and corrosion-resistant joint, by means of a joining material, between a first body and a second body each made of sintered, polycrystalline alumina ceramic with a purity greater than 92 wt. % or of sapphire. The joining material i

This process serves to form a long-time-vacuum-tight, high-strength, and corrosion-resistant joint, by means of a joining material, between a first body and a second body each made of sintered, polycrystalline alumina ceramic with a purity greater than 92 wt. % or of sapphire. The joining material is interposed in the form of a paste, a foil, or a slip between the first body and the second body. The joining material has been made from 1) an agglomerate-free, highly disperse, high-purity .alpha.-alumina powder with particles of as high a degree of calcination as possible and of a size not exceeding 100 nm (=10.sup.-7 m), 2) an anorganic oxidic powder of an auxiliary sintering agent with particles of approximately the same size as the particle size of the .alpha.-alumina powder, 3) an organic vehicle which is dissolved or suspended in an organic or aqueous solvant and in which the particles of the respective powder are distributed as evenly as possible. Instead of the anorganic oxidic powder of an auxiliary sintering agent an anorganic oxidic auxiliary sintering agent produced chemically as envelopes around or attachment to the particles of the .alpha.-alumina powder can be used, the total .alpha.-alumina and auxiliary-sintering-agent content of the paste, the foil, or the slip ranging between 50% and 70%. After interposing the joining material the bodies are heated to a temperature of not more than 1,300.degree. C. and then allowing them to cool down.

대표청구항 ▼

[ We claim:] [1.] A process for forming a long-time-vacuum-tight, high-strength, and corrosion-resistant joint, by means of a joining material, between a first body and a second body each made of sintered, polycrystalline alumina ceramic with a purity greater than 92 wt. % or of sapphire, said proce

[ We claim:] [1.] A process for forming a long-time-vacuum-tight, high-strength, and corrosion-resistant joint, by means of a joining material, between a first body and a second body each made of sintered, polycrystalline alumina ceramic with a purity greater than 92 wt. % or of sapphire, said process comprising steps of:interposing the joining material in the form of a paste, a foil, or a slip between the first body and the second body,the joining material having been made froman agglomerate-free, high-purity .alpha.-alumina powder with particles of a size not exceeding 100 nm (=10.sup.-7 m),an anorganic oxidic powder of an auxiliary sintering agent with particles of a size not exceeding 100 nm, and an organic vehicle which is dissolved or suspended in an organic or aqueous solvant and in which the particles of the respective powder are substantially evenly distributed,with the total .alpha.-alumina and auxiliary-sintering-agent content of the paste, the foil, or the slip ranging between 50% and 70%,or with the joining material having been made froman agglomerate-free, high-purity .alpha.-alumina powder with particles of a size not exceeding 100 nm (=10.sup.-7 m),an anorganic oxidic auxiliary sintering agent produced chemically as envelopes around or attachment to the particles of the .alpha.-alumina powder, andan organic vehicle dissolved or suspended in an organic or aqueous solvant,with the total .alpha.-alumina and auxiliary-sintering-agent content of the paste, the foil, or the slip ranging between 50% and 70%; andbeating the bodies to a temperature of not more than 1,300.degree. C. and then allowing them to cool down,with the alumina content of the joint after cooling being at least 95 wt. % and the auxiliary-sintering-agent content after cooling being not more than 5 wt. %.