Abstract: Metal objects are treated by anodising the metal object in contact with an aqueous electrolyte, and then subjecting the anodised metal object to a reversed voltage. The anodising is performed in two stages, firstly to passivate with the formation of an oxide layer, and secondly to form regions in the oxide layer having a higher oxygen to metal atom ratio, for example pits or caps, in this oxide layer. The second stage of anodising is performed by applying a multiplicity of voltage cycles, each voltage cycle involving ramping the voltage between a lower threshold voltage and an upper threshold voltage, and then returning to the lower threshold voltage. The reversed voltage step forms a hydrous metal oxide in the regions of higher oxygen to metal atom ratio, and the oxide layer and hydrous metal oxide together constitute a surface layer which is integral with the metal object, and has ion exchange capacity.

Abstract: Metal objects are treated by anodising the metal object in contact with an aqueous electrolyte, and then subjecting the anodised metal object to a reversed voltage. The anodising is performed in two stages, firstly to passivate with the formation of an oxide layer, and secondly to form regions in the oxide layer having a higher oxygen to metal atom ratio, for example pits or caps, in this oxide layer. The second stage of anodising is performed by applying a multiplicity of voltage cycles, each voltage cycle involving ramping the voltage between a lower threshold voltage and an upper threshold voltage, and then returning to the lower threshold voltage. The reversed voltage step forms a hydrous metal oxide in the regions of higher oxygen to metal atom ratio, and the oxide layer and hydrous metal oxide together constitute a surface layer which is integral with the metal object, and has ion exchange capacity.

Abstract: In a process for anodizing a metal object (12), the metal object (12) is contacted with an anodizing electrolyte (32), and is first pre-anodized so as to grow a thin oxide film on the surface. The microscopic surface area is then deduced from electrical measurements either during pre-anodizing or on the pre-anodized surface. The metal object (12) can then be anodized. This is applicable when treating an implant to provide a surface that has the ability to incorporate biocidal material such as silver ions. The pre-anodizing uses a low voltage, for example no more than 2. V, and may take less than 120 seconds.

Abstract: Metal objects are treated by anodizing (P, SE) the metal object in contact with an acidic solution, and then subjecting the anodized metal object to a reversed voltage (VR). The anodizing is performed in two stages, firstly to passivate (P) with the formation of a surface layer, and secondly to form pits in this surface layer (SE). The second stage (SE) of anodizing is performed at a lower voltage than the first stage (P). After the reversed voltage step (VR) the metal object is then contacted with a biocidal metal-containing solution. Biocidal metal is absorbed into the surface of the metal object, resulting in improved biocidal properties. The lower voltage of the second stage anodizing (SE) results in reduced processing time.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer may be grown from the metal substrate, by anodising, and the biocidal material incorporated in it by ion exchange. Alternatively the layer may be deposited by electroplating, followed by diffusion bonding so as to become integral with the metal substrate. In either case, silver is a suitable biocidal material; and both the release rate and the quantity of biocidal material should be low to avoid toxic effects on body cells. Electropolishing the surface before formation of the surface layer is also beneficial, and this may be achieved by electropolishing.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer may be grown from the metal substrate, by anodizing, and the biocidal material incorporated in it by ion exchange. Alternatively the layer may be deposited by electroplating, followed by diffusion bonding so as to become integral with the metal substrate. In either case, silver is a suitable biocidal material; and both the release rate and the quantity of biocidal material should be low to avoid toxic effects on body cells. Electropolishing the surface before formation of the surface layer is also beneficial, and this may be achieved by electropolishing.

Abstract: Metal objects are treated by anodising (P, SE) the metal object in contact with an acidic solution, and then subjecting the anodised metal object to a reversed voltage (VR). The anodising is performed in two stages, firstly to passivate (P) with the formation of a surface layer, and secondly to form pits in this surface layer (SE). The second stage (SE) of anodising is performed at a lower voltage than the first stage (P). After the reversed voltage step (VR) the metal object is then contacted with a biocidal metal-containing solution. Biocidal metal is absorbed into the surface of the metal object, resulting in improved biocidal properties. The lower voltage of the second stage anodising (SE) results in reduced processing time.

Abstract: Metal objects are treated by anodising (P, SE) the metal object in contact with an acidic solution, and then subjecting the anodised metal object to a reversed voltage (VR). The anodising is performed in two stages, firstly to passivate (P) with the formation of a surface layer, and secondly to form pits in this surface layer (SE). The second stage (SE) of anodising is performed at a lower voltage than the first stage (P). After the reversed voltage step (VR) the metal object is then contacted with a biocidal metal-containing solution. Biocidal metal is absorbed into the surface of the metal object, resulting in improved biocidal properties. The lower voltage of the second stage anodising (SE) results in reduced processing time.

Abstract: A metal object is treated to form an integral surface layer by: (a) immersing the metal object in an anodising electrolyte, and passivating the metal to form an anodised layer on the metal object; (b) continuing the application of a potential to modify the surface layer; (c) then treating the metal object with a chemical reducing agent so a hydrous metal oxide is formed; and (d) then contacting the metal object with a solution containing a biocidal material so as to incorporate biocidal material into the surface layer.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer is grown by anodizing at a voltage between 50 and 150 V, and the biocidal material incorporated in it by ion exchange. This produces a significantly harder surface than anodizing at low voltage, and generates pits containing ion-absorbing material.

Abstract: A metal implant for use in a surgical procedure is provided with a surface layer that is integral with the metal substrate, and which incorporates a biocidal material. The surface layer may be grown from the metal substrate, by anodizing, and the biocidal material incorporated in it by ion exchange. Alternatively the layer may be deposited by electroplating, followed by diffusion bonding so as to become integral with the metal substrate. In either case, silver is a suitable biocidal material; and both the release rate and the quantity of biocidal material should be low to avoid toxic effects on body cells. Electropolishing the surface before formation of the surface layer is also beneficial, and this may be achieved by electropolishing.

Abstract: Metal implants (10) are treated by anodising the surface (11, 12) in contact with an electrolyte, and then briefly subjecting the anodised surface to a reversed voltage. During a first anodising stage the surfaces are passivated, while during a subsequent anodising stage pits are formed in the passivating surface layer. Rough portions (15) of the surface, in particular portions produced by plasma spraying of metal powder, are sealed with a watertight cover (20) during at least part of the anodising process. After rinsing, biocidal metal ions are subsequently absorbed into the surface of the implant. This provides the implant with biocidal properties. The use of the cover (20) enables a more uniform geometric distribution of biocidal metal ions to be achieved.

Abstract: Metal objects are treated by anodising the metal object in contact with an acidic solution, and then subjecting the anodised metal object to a reversed voltage (compared to the anodising voltage). The thus-treated metal object is then contacted with a biocidal metal-containing solution. Biocidal metal is deposited on the surface of the metal object, resulting in improved biocidal properties.

Abstract: In a process for anodising a metal object (12), the metal object (12) is contacted with an anodising electrolyte (32), and is first pre-anodised so as to grow a thin oxide film on the surface. The microscopic surface area is then deduced from electrical measurements either during pre-anodising or on the pre-anodised surface. The metal object (12) can then be anodised. This is applicable when treating an implant to provide a surface that has the ability to incorporate biocidal material such as silver ions. The pre-anodising uses a low voltage, for example no more than 2. V, and may take less than 120 seconds.