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2 2002

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Microstructure of metallic layers sintered on nitride ceramics depending of the chemical composition of interlayers

Olesińska W.

Materiały Elektroniczne

2002

T. 30, nr 3

28-38

The effects of the oxygen and titanium contents in the reactive layer deposited on nitride ceramics on the wettability and sintering capability of the metallic layers were examined. The deposited metallic layers were standard Mo and Mn layers with the oxygen content ranging from 0 to 40 at.% and the titanium content from 0 to 8 at.%. The layers were sintered at a temperature between 1573 and 1653 K in a hydrogen atmosphere (dew point - 203 K). In the a transition layers, between the Al2O3, or AIN ceramic material and the metallic layer, a continuous glass layer is formed on the ceramic surface, which wets very well both the substrate and the metallic powders.The microstructure of the metallic layers was examined using a scanning electron microscope and an electron probe. It has been found that both Al and Si migrate strongly to the interface layer. The microstructure of the metallic layers sintered on AIN differs from that of the layers sintered on alumina ceramics. In the interface layer formed between the ceramic material and the metallic layer, a continuous glass layer forms on the ceramic surface; the glass wets very well both the substrate and the metallic powders. The metallic layer is compact, and the solder does not flow in-between the grains. Based on the results of the microstructural examinations, the mechanisms of the sintering of Al and AIN ceramics are compared.

Properties of AlN-metal joints depending on the chemical composition of interlayers.

Włosiński W.K., Olesińska W.

Advances in Manufacturing Science and Technology

2002

Vol. 26, nr 1

17-28

The results of examinations of the metallic molybdenum/manganese layers sintered on ceramic substrates in an atmosphere of dry hydrogen (dew point of 203 K) are presented. The effect of the oxygen and titanum contents in the MoMn layers produced on AlN ceramics, was examined. The layers examined were standard Mo, Mn layers in which the oxygen content was varied from 0 to 40 at.% and the titanium content from 0 to 3,8 at.%. The layers were sintered at temperatures of 1623 K and 1663 K in a hydrogen atmosphere of a dew point of 203 K (-70 degrees C). The microstructure of the metallic layers was examined using a scanning electron microscope and an electron probe. It has been found that both Al and Si migrate strongly to the interface layer. The microstructure of the metallic layers sintered on AlN differs from that of the layers sintered on alumina ceramics. In the interface layer formed between the ceramic material and the metallic layer, a continuous glass layer forms on the ceramic surface; the glass wets very well both the substrate and the metallic powders. The metallic layer is compact, and the solder does not flow in-between the grains. Based on results of the microstructural examinations, the mechanisms of the sintering of alumina and AlN ceramics are compared. The results of examination of the mechanical strength of the ceramics/ceramics and ceramics/metal (copper and FeNi42 alloy) joints performed by the three-point bending method are reported. It has been found that the mechanical strength of the joints depends on the contents of oxygen and titanium in the metallic layer. All joints brazed by "hard" solders as well as "soft" solders have a continuous microstructure and do not fail under the action of thermal stresses.

Przedstawiono wyniki badań warstw metalicznych molibden/mangan spiekanych w atmosferze suchego wodoru (p. rosy 203 K). Do badań stosowano standardowe wastwy metaliczne MoMn o zawartości tlenu w zakresie 0-40% at. oraz zawartości tytanu od 0 do 3,8% at. Warstwy te spiekano w temperaturze 1623 i 1663 K w atmosferze wodoru o punkcie rosy 203 K. Stwierdzono znaczną migrację zarówno Al, jak i Si do warstwy granicznej. Mikrostruktura warstw metalicznych spiekanych na ceramice z azotku glinu różni się od mikrostruktury warstw metalicznych spiekanych na ceramice korundowej. W warstwach przejściowych utworzonych pomiędzy ceramiką a warstwami metalicznymi obserwowano na powierzchni ceramiki ciąglą warstwę szkła dobrze zwilżającą zarówno podłoże, jak i proszki metaliczne. Warstwa metaliczna jest zwarta, lut nie wnika między ziarna. Wyniki badań mikrostrukturalnych były podstawą do określenia mechanizmu spiekania warstw metalicznych dla ceramiki korundowej i ceramiki z AlN. Podano wyniki badań wytrzymałości mechanicznej złączy ceramika-ceramika i ceramika-metal (miedź i stop FeNi42) metodą zginania trójpunktowego oraz metodą ścinania. Stwierdzono, że wytrzymałość złączy zależy od zawartości tlenu i tytanu w warstwie metalicznej. Złącza lutowane zarówno lutami 'twardymi", jak i "miękkimi" zachowują ciągłość mikrostruktury, nie ulegają zniszczeniu pod wpływem naprężeń cieplnych.