Patent Application
20190189312
The present invention relates to a pretreatment of a thick-film aluminum electrode; more particularly, to significantly improving the evenness and oxygen content of the surface of the thick-film aluminum electrode through a purely mechanical treatment, a purely chemical alkaline/acid washing treatment, a mixture of mechanical and chemical treatments or a chemical proper anodizing treatment.
Currently, metal silver can be easily used as an electrode for subsequent nickel- or tin-plating. Yet, because silver is a noble metal, a conductive material mainly made of noble metal silver powder will result in expensive material cost and is susceptible to price ups and downs. For reducing material cost, a thick-film electrode of base metal aluminum is chosen to replace a thick-film electrode of noble metal silver. However, roughness and easy oxidization of the surface of the thick-film aluminum electrode will cause problem to subsequent metal plating.
Generally, a thick-film aluminum electrode has a rough surface with pores. As shown in
The thick-film silver electrode has smooth surface and is not easily oxidized, which can be easily applied for subsequent electroplating. But, silver is a noble metal, whose cost is high and unstable. If the substituent thick-film aluminum electrode is considered, its rough and easily oxidized surface will cause difficulty in its application for subsequent electroplating. Hence, the prior arts do not fulfill all users' requests on actual use.
The main purpose of the present invention is to significantly improve evenness and oxygen content of the surface of a thick-film aluminum electrode through a purely mechanical treatment, a purely chemical alkaline/acid washing treatment, a mixture of mechanical and chemical treatments or a chemical proper anodizing treatment, where the novel thick-film aluminum electrode has similar quality as a thick-film electrode of noble metal silver for subsequent metal plating.
To achieve the above purpose, the present invention is a pretreatment of a thick-film aluminum electrode for metal plating, where a thick-film aluminum electrode is pretreated before performing subsequent metal plating; the thick-film aluminum electrode is pretreated with a purely mechanical treatment, a purely chemical alkaline or acid washing treatment, a mixture of mechanical and chemical treatments or a chemical proper anodizing treatment; the surface of the thick-film aluminum electrode is made even and alumina, a nonconductive substance, on the surface is removed; the thick-film aluminum electrode obtains a surface with evenness and low oxygen content; and the thick-film aluminum electrode has similar quality as a thick-film electrode of noble metal silver for subsequent electroplating. Accordingly, a novel pretreatment of a thick-film aluminum electrode for metal plating is obtained.
The present invention will be better understood from the following detailed description of the preferred embodiment according to the present invention, taken in conjunction with the accompanying drawings, in which
The following description of the preferred embodiment is provided to understand the features and the structures of the present invention.
Please refer to
On using the present invention, the surface of a thick-film aluminum electrode is pretreated with a mechanical grinding, a chemical alkaline/acid washing or a chemical anodizing for a certain period of time. Therein, the evenness of the thick-film aluminum electrode is significantly improved and its oxygen content is greatly reduced for easily applying subsequent metal plating.
In a state-of-use of the mechanical grinding, the present invention mixes a chip resistor of thick-film aluminum electrode with a media of iron beads at a certain ratio in a cylindrical roller, where the media of iron beads has each bead a diameter of 0.5˜0.81 millimeters and the certain ratio for mixed the chip resistor of thick-film aluminum electrode with the media of iron beads is 1:10 for grounding 8 hours. Thus, the media of iron beads frictions with the chip resistor of thick-film aluminum electrode to make the surface of thick-film aluminum electrode even with alumina removed. Hence, the surface of the thick-film aluminum electrode obtains evenness greatly improved with the nonconductive substance alumina removed. In
The present invention plates nickel and tin on the chip resistor of thick-film aluminum electrode after a mechanical grinding. Therein, after nickel is plated under a current of 21 amperes (A) for 40 minutes (min) and tin is plated under a current of 7 A for 40 min, the chip resistor of thick-film aluminum electrode is fabricated. In
In a state-of-use of the chemical alkaline/acid washing, a chip resistor of thick-film aluminum electrode is put in a cylindrical roller and immersed in an alkaline solution (0.25M NaOH, temperature: 50° C.) or an acid solution (nickel sulfate: 410 g/l, sulfuric acid: 10%, temperature: 65° C.) for rolling about 15 min. After rolling, the alkaline or acid solution etches the chip resistor of thick-film aluminum electrode to make the surface of thick-film aluminum electrode even with alumina removed. Thus, the surface of thick-film aluminum electrode is significantly improved in evenness and the non-conductive substance alumina is removed. In
In a state-of-use of the chemical anodizing, a chip resistor of thick-film aluminum electrode is put in a cylindrical roller and immersed in an acid solution (phosphoric acid: 1/10 Vol %, temperature: 2˜65° C.). A platinum electrode is used as a cathode and the chip resistor of thick-film aluminum electrode is used as an anode to be applied with a voltage of 30 volts for processing the chemical anodizing. After being rolled for about 15 minutes, the chip resistor of thick-film aluminum electrode has the surface made even with alumina removed through an electrolytic reaction (Al→Al3++3e−). Thus, the surface of thick-film aluminum electrode is significantly improved in evenness and the non-conductive substance alumina is removed. A plurality of the thick-film aluminum electrodes pretreated with the chemical anodizing for different periods of time are plated with nickel. In
Accordingly, the present invention solves the problem of the subsequent metal plating for the thick-film aluminum electrode. Through the purely mechanical pretreatment, the pure chemical alkaline/acid washing pretreatment, the mixture of the mechanical and chemical pretreatments or the chemical proper anodizing pretreatment, the evenness and oxygen content of the thick-film aluminum electrode are significantly improved. Thus, the pretreated thick-film aluminum electrode has similar quality as a thick-film electrode of noble metal silver for subsequent metal plating.
To sum up, the present invention is a pretreatment of a thick-film aluminum electrode for metal plating, where a thick-film aluminum electrode is pretreated for subsequent metal plating; the pretreatment is a purely mechanical treatment, a purely chemical alkaline/acid washing treatment, a mixture of mechanical and chemical treatments or a chemical proper anodizing treatment; the surface of the thick-film aluminum electrode is made even and alumina, a nonconductive substance, on the surface is removed; the thick-film aluminum electrode obtains a surface with evenness and low oxygen content; and, hence, the novel thick-film aluminum electrode has similar quality as the thick-film electrode of noble metal silver for subsequent metal plating.
The preferred embodiment herein disclosed is not intended to unnecessarily limit the scope of the invention. Therefore, simple modifications or variations belonging to the equivalent of the scope of the claims and the instructions disclosed herein for a patent are all within the scope of the present invention.
