Abstract: A mesoporous metal oxide crystal material is provided. This material has realized a large specific surface area by controlling crystallite diameter in the formation of metal oxide crystals, and preventing collapse of the mesoporous structure associated with the crystal growth upon calcinations, to improve sensitivity and effectiveness of a gas detector element of the metal oxide material and photocatalyst. A metal oxide precursor is filled in the pores of a mesoporous template, and the resulting mesoporous silica having the metal oxide precursor filled therein is added to a hydrolytic aqueous solution to thereby promote hydrolysis of the metal oxide precursor in the interior of the pores and produce a large number of metal oxide crystals in the interior of the pores. Next, the metal oxide fine crystals are heated at 300° C. or higher for calcination with the crystallite diameter controlled in the range of 1 nm to 2 nm.

Abstract: The present invention relates to an electroless gold plating solution, a method of plating by using the same, and an electronic device plated with gold by using the same.According to the present electroless gold plating solution, the plating solution components contain no cyanide ions, the amount of a reducing agent used is small, and gold plating can be carried out without causing the gold plating on conducting paths having a fine interval between them to short-circuit the conducting paths.Therefore, according to the method of gold plating by using said electroless gold plating solution, a plating method that is safe in the plating work and in the treatment of its waste liquor can be accomplished. The method has a feature that the method can provide an electronic device on which parts can be mounted highly densely, and wherein the joint reliability to the parts is high.

Abstract: The present invention provides an electroless gold plating solution comprising essentially gold ions, a complexing agent, and a reducing agent, characterized by further containing a reduction promoter which has a function of giving electrons to an oxidant, the oxidant being produced from oxidation of the reducing agent with the gold ions being reduced, to change the oxidant to the original reducing agent. The present invention also provides a process for conducting electroless gold plating by bringing a substrate into contact with the electroless gold plating solution. The plating solution is excellent in the stability for gold plating of high deposition rate. Thus the present invention allows the electroless gold plating to be performed stably at a higher deposition rate.

Abstract: The present invention relates to an electroless gold plating solution, a method of plating by using the same, and an electronic device plated with gold by using the same.According to the present electroless gold plating solution, the plating solution components contain no cyanide ions, the amount of a reducing agent used is small, and gold plating can be carried out without causing the gold plating on conducting paths having a fine interval between them to short-circuit the conducting paths.Therefore, according to the method of gold plating by using said electroless gold plating solution, a plating method that is safe in the plating work and in the treatment of its waste liquor can be accomplished. The method has a feature that the method can provide an electronic device on which parts can be mounted highly densely, and wherein the joint reliability to the parts is high.

Abstract: An electroless gold plating solution comprising a thiosulfato gold(I) complex, a thiosulfate, thiourea, a pH regulator and a stabilizer. The electroless gold plating solution shows a plating rate and a plating solution stability comparable to those of conventional gold plating solutions containing cyanide ions, and requires a smaller amount of reducing agent to be used therein. Further, the electroless gold plating solution is safe because it does not contain cyanide ions.

Abstract: An electroless gold plating solution comprising a thiosulfato gold(I) complex, a thiosulfate, thiourea, a pH regulator and a stabilizer. The electroless gold plating solution shows a plating rate and a plating solution stability comparable to those of conventional gold plating solutions containing cyanide ions, and requires a smaller amount of reducing agent to be used therein. Further, the electroless gold plating solution is safe because it does not contain cyanide ions.