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US 11,453,941 B2Granted
Cerium oxide coating, its preparation and use
AssigneeCity University of Hong Kong
InventorsKwok Yan Li, Zhen Shi, Po Wan Shum, Zhifeng Zhou
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AssigneeCity University of Hong Kong
InventorsKwok Yan Li, Zhen Shi, Po Wan Shum, Zhifeng Zhou
Estimating the term…
A method for preparing a CeOx coating on a surface of a substrate includes depositing a CeOx coating on the surface by means of a reactive magnetron sputtering from a pure cerium target. The CeOx coating can be transparent for visible light. A method for reducing the adhesion of a tissue material such as from a human to a surface of a medical instrument, for reducing the water condensation and improving the heat transfer performance of a heat exchanger surface of a substrate, and for reducing corrosion of a surface of a substrate includes depositing a CeOx coating on the substrate by means of a reactive magnetron sputtering from a pure cerium target. This provides an environmentally friendly preparation of the CeOx coating with no need for organic solvents or volatile organic compounds. The CeOx coating has good hydrophobicity, enhanced hardness, exceptionally high wear resistance, and superior thermal stability.
A method for preparing a crystallized CeOx coating having a cubic fluorite structure and a thickness of about 10 nm to about 100 nm on a surface of a substrate in an unbalanced magnetron sputtering system comprising a step of depositing the crystallized CeOx coating essentially consisting of Ce2O3 and/or CeO2 on the surface by means of a reactive magnetron sputtering from a cerium target having a purity of at least about 99.9%, wherein the reactive magnetron sputtering is carried out, in a closed magnetic field coupling arrangement, with a pulsed sputtering voltage applied to the cerium target of about −200 V to about −500 V pulsed in a frequency range of about 100 kHz to about 350 kHz, a pulsed substrate bias voltage of between about −60 V and −100 V, at a temperature between about 20° C. and about 30° C., and with a bias ion current density of between about 1 mA/cm2 and about 5 mA/cm2, wherein the reactive magnetron sputtering is carried out in a deposition chamber filled with a gas mixture of a working gas comprising argon for sputtering the cerium target and a reactive gas comprising oxygen arranged to react with atoms sputtered from the cerium target during the step of depositing of the crystallized CeOx coating on the substrate, and wherein the gas mixture includes an oxygen to argon flow ratio in a range of about 20% to about 100%.
A method for reducing the adhesion of a tissue material to a surface of a medical instrument in an unbalanced magnetron sputtering system comprising depositing a crystallized CeOx coating having a cubic fluorite structure and a thickness of about 10 nm to about 100 nm, said crystallized CeOx coating essentially consisting of Ce2O3 and/or CeO2 on the surface by means of a reactive magnetron sputtering from a cerium target having a purity of at least about 99.9%, wherein the reactive magnetron sputtering is carried out, in a closed magnetic field coupling arrangement, with a pulsed sputtering voltage applied to the cerium target of about −200 V to about −500 V pulsed in a frequency range of about 100 kHz to about 350 kHz, a pulsed substrate bias voltage of between about −60 V and −100 V, at a temperature between about 20° C. and about 30° C., and with a bias ion current density of between about 1 mA/cm2 and about 5 mA/cm2, wherein the reactive magnetron sputtering is carried out in a deposition chamber filled with a gas mixture of a working gas comprising argon for sputtering the cerium target and a reactive gas comprising oxygen arranged to react with atoms sputtered from the cerium target during the depositing of the crystallized CeOx coating on the substrate, and wherein the gas mixture includes an oxygen to argon flow ratio in a range of about 20% to about 100%.
A method for reducing water condensation and improving heat transfer performance of a heat exchanger surface of a substrate in an unbalanced magnetron sputtering system comprising depositing a crystallized CeOx coating having a cubic fluorite structure and a thickness of about 10 nm to about 100 nm, said crystallized CeOx coating essentially consisting of Ce2O3 and/or CeO2 on the heat exchanger surface by means of a reactive magnetron sputtering from a cerium target having a purity of at least about 99.9%, wherein the reactive magnetron sputtering is carried out, in a closed magnetic field coupling arrangement, with a pulsed sputtering voltage applied to the cerium target of about −200 V to about −500 V pulsed in a frequency range of about 100 kHz to about 350 kHz, a pulsed substrate bias voltage of between about −60 V and −100 V, at a temperature between about 20° C. and about 30° C., and with a bias ion current density of between about 1 mA/cm2 and about 5 mA/cm2, wherein the reactive magnetron sputtering is carried out in a deposition chamber filled with a gas mixture of a working gas comprising argon for sputtering the cerium target and a reactive gas comprising oxygen arranged to react with atoms sputtered from the cerium target during the deposition of the crystallized CeOx coating on the substrate, and wherein the gas mixture includes an oxygen to argon flow ratio in a range of about 20% to about 100%.
A method for reducing corrosion of a surface of a substrate in an unbalanced magnetron sputtering system comprising depositing a crystallized CeOx coating having a cubic fluorite structure and a thickness of about 10 nm to about 100 nm, said crystallized CeOx coating essentially consisting of Ce2O3 and/or CeO2 on the surface by means of a reactive magnetron sputtering from a cerium target having a purity of at least about 99.9%, wherein the reactive magnetron sputtering is carried out, in a closed magnetic field coupling arrangement, with a pulsed sputtering voltage applied to the cerium target of about −200 V to about −500 V pulsed in a frequency range of about 100 kHz to about 350 kHz, a pulsed substrate bias voltage of between about −60 V and −100 V, at a temperature between about 20° C. and about 30° C., and with a bias ion current density of between about 1 mA/cm2 and about 5 mA/cm2, wherein the reactive magnetron sputtering is carried out in a deposition chamber filled with a gas mixture of a working gas comprising argon for sputtering the cerium target and a reactive gas comprising oxygen arranged to react with atoms sputtered from the cerium target during the depositing of the crystallized CeOx coating on the substrate, and wherein the gas mixture includes an oxygen to argon flow ratio in a range of about 20% to about 100%.
Dependencies are inferred from the claim text.