JPS5816076A - Etching method - Google Patents

Abstract

PURPOSE:To form a good and uniform etching surface inexpensively by virtue of a metallic coating obtained by immersing iron of a cathode base material in an acid soln. contg. inorg. neutral chlorides. CONSTITUTION:Alkali metallic chlorides such as NaCl, KCl or the like alakline earth metallic chlorides such as CaCl2, MgCl2 or the like, and NH4Cl are used as inorg. neutral chlorides, and said chlorides are contained in an acid soln. at about 1wt%- satd. wt. Hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, etc. are used as acids in the form of about 1-30% concn. soln. The etching soln. is maintained above ordinary temp., more particularly at about 30-60 deg.C and iron is immersed for about 30min- several hours in said soln. By such coating of metal on the surface of iron, a good cathode is obtained at a low cost. The method is effective for stainless steel, Ni or Ti single material and their alloys, etc. as a metallic base material in addn. to iron and is not limited by the shapes of the base materials.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel metal surface etching method. Specifically, the IHR of the substrate surface W10 etching method, which is characterized in that the surface of the metal substrate is partially coated with an acid solution containing an inorganic O neutral chloride salt, is 0.

Conventionally, metal coatings on metal substrates such as iron using sintering, chemical metal deposition, or electroplating techniques have been applied by applying acid to the surface of the substrate as well as removing rust as an electric layer. 11IIIi
It is known to perform an etching process using a tk etching method. A method has been proposed for manufacturing a true cathode by improving the adhesion with the coating material by first treating the iron base material with perchloric acid*ii. A cathode that is treated with a solution and coated with a cathode active substance on a round iron base material by hooking, plating, etc., has a lower performance compared to a cathode that is not treated with perchloric acid when used, for example, for alkaline salt water electrolysis. Since the hydrogen overvoltage is low and the adhesion between the base material and the coating material is good, the activity as a cathode generally decreases little over time.

However, Haruka #1 Takashun's reagent is expensive, and if metal ions such as iron are present during the perchloric acid treatment process, self-synthesis occurs and the concentration decreases. Because of the problem of having to replenish water, the method of treating with perchloric acid increases the total cost including the transportation of the entire subsequent process.

The present invention is the result of intensive research into a new etching method for the purpose of obtaining a cathode with particularly high corrosion resistance at a low cost, similar to the above-mentioned perchloric acid treatment.

The object can be achieved by treating the surface of a metal substrate with an acid solution containing an inorganic neutral chloride, which is one aspect of the present invention.

Therefore, although the present invention is preferably employed for etching 511-valent substrates, it is not limited thereto, but is also applicable to etching of general metal substrates.

Common metal base materials include steel, stainless steel, nickel, and titanium alone, as well as metals containing these as components, and are very effective against iron. The shape of the metal base material is not limited to a plate, a steel bar, etc., and may be appropriately selected and used according to the shape of the cathode, etc., as necessary.

The acids used in the present invention include hydrochloric acid and sulfuric acid.

Anything that increases the hydrogen ion concentration, such as phosphoric acid and nitric acid, may be used. As neutral chlorides, alkali metal chlorides such as potassium chloride, alkaline earth metal chlorides such as calcium chloride and magnesium chloride, or ammonium chloride are preferably used. According to the present invention, it is extremely important to use the method described above in combination with an inorganic neutral chloride, and the etching effect is as good as or better than that of perchloric acid treatment.

On the other hand, when the neutral chloride of Shun or Hiro Inuki is used alone, for example, when the iron base material is immersed in an acid at a high temperature of #11 degrees, the Aisha base material undergoes significant general corrosion and thinning. However, in an inorganic neutral chloride solution, iron is locally corroded and turns into a cocoon of debris and red rust, making it undesirable as an etching surface.

However, by treating with an acid and an inorganic neutral chloride in the present invention, the surface II of the metal substrate is uniformly etched, increasing the surface area and causing physical scratches. Therefore, a very smooth surface can be obtained for subsequent metal coating such as plating.

Moreover, since the acid or inorganic neutral chloride used in this invention is a general-purpose product, it is significantly cheaper than the conventionally used perchloric acid, and it is easy to handle in a partial filtration process. be.

The O treatment method of the present invention is generally accomplished by immersion in an acid solution containing an inorganic neutral chloride. A preferred embodiment is an aqueous solution having an acid concentration of 11 to 50 weight X, and an inorganic neutral chloride in an amount of 1 weight For example, the substrate may be soaked for several hours. Of course, the treatment with Suntokake containing inorganic neutral chloride is not limited to these O methods.

It is generally known that as a pretreatment for metal coating such as plating or for painting, pickling or metal cleaning agent treatment, and in some cases etching treatment, are performed as surface treatments such as rust removal. Also in the present invention, it is preferable to carry out the above-mentioned omniscient pretreatment such as %I-h0, for example, to perform the rust removal operation in advance.

Electrode layered surface by the etching method of the present invention 2 Surface @
Variation measurement result example 2 Thickness 1.5 sm + 0 made of soft steel expanded metal
, s s awIO cathode substrate in Example 10 Table 1 0JK
1, 3, 5, 9, and 100 solutions were used for etching, and then plated with Rodan nickel using a plate having the composition shown in Table 3. Using this as a cathode and a platinum plate as a counter electrode, electrolysis was carried out at 85°C in a 20 wt.
Got the results.

Example 3 An electrode prepared in exactly the same manner as in Example 2 except that the substrate shape was changed to 1d- was used as a cathode of a filter press electrolytic cell. The anode was a titanium lath coated with ruthenium oxide and titanium oxide, and the diaphragm was OsuFion ■324 (Varcro tetra-sulfonic acid cation exchange membrane) manufactured by Depon.

Table 6 summarizes the changes in electrode potential over time when salt electrolysis was performed under the Hata condition shown in Table 5.

Claims (1)

[Claims] 1) An etching method based on partially layering the surface of the metal group #O with an acid solution containing an inorganic neutral chloride 3) A patent claim in which the metal base material is a cathode base material Etching method described in Paragraph 1 of Ohan S Iris 3) Etching method described in Paragraph 1 of Patent Claim 01111 in which the metal and material is iron 4) mall ('1 Neutral chloride is an alkali metal chloride 5) The etching method according to claim 1, wherein the alkali metal chloride is an alkaline earth metal chloride or ammonium chloride. Etching method 6) Etching method described in Clause 4 in which the alkaline earth metal chloride is calcium chloride or madanesium chloride 1) - If the solution is hydrochloric acid, sulfuric acid or phosphoric acid, nitric acid is added. 8) The etching method according to claim 1, wherein the acid concentration of the acid solution is 1 to sO weight loss 9) The 5IWL of neutral chloride to the acid solution The etching method according to claim 1, wherein is from 1 weight X to saturation amount.