Schwarzkopf Technologies Corporation

Wolfgang Hohenauer

The present invention relates to an oxide coating layer for improving the thermal emissivity of metallic X-ray tube anodes as well as improving the layer properties and effects displayed by the oxide coating. The oxide coating layer includes 1-20% by weight, and preferably, 4-7% by weight, of aluminum oxide. The layer additionally includes small proportions of other compounds and contains the oxides of the metals Ti and Zr and is applied to the x-ray anode by standard deposition processes. It is essential that the titanium dioxide content is less than 20% by weight of the oxide coating layer and the zirconium oxide content is greater than 60% by weight of the oxide coating layer. The coating layer may also include a stabilizing component, such as CaO. As a result, the deposition of such oxides or oxide mixtures is substantially better than hitherto known, and the anodes thus produced can be further processed to produce useable oxide layers without adverse effect to the important properties of layer adhesion and thermal emission coefficient.

X-ray tube anode with oxide coating

The invention relates to enhancing the thermal emissivity of metal X-ray tube anodes by means of applying an oxide coating to the anode. The oxide coating layer is formed of a mixture of zirconium oxide, titanium oxide, aluminum oxide and/or calcium oxide, with silicon oxide added from about 1-20% by weight of said oxide coating layer. Preferably, the coating includes from about 4-7% by weight of silicon oxide. The oxide coating layer is then applied to the anode pursuant to a standard method such as plasma spraying. The oxide coating, as formulated, displays improved layering characteristics over prior formulations while retaining good thermal emissivity and adhesive properties. Moreover, the formulation according to the invention enables an improved application to the anode of such oxides or oxide compounds over previous formulations, without negatively affecting the layer adhesion or thermal emission coefficient properties of the coating. Small quantities of other stabilizing oxide compounds may additionally be added to the oxide coating layer.

An X-ray anode, in particular a rotary anode, having a parent body made of a carbon-containing refractory material. To improve the thermal radiation characteristics of the anode, the anode is provided with an oxidic top layer outside the focal spot or the focal track regions which contains a homogeneously fused phase. A two-ply interlayer arrangement, containing a first-ply of molybdenum and/or tungsten, and a second oxidic ply of Al.sub.2 O.sub.3, containing 1-30% by weight of TiO.sub.2, is arranged between the parent body and the oxidic top layer. As a result of this interlayer structure, the fusion of the oxidic top layer so as to form a homogeneous phase becomes possible without problems. In addition, the ageing resistance of the thermal emission coefficient ('.epsilon.') is substantially improved.

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Kufstein, Austria

Wolfgang Hohenauer