Etching solutions treatment

The surface segregation of Sr is of particular interest as SrO affects the surface reactivity and the activation behavior of the LSM electrode. Jiang and Love [36] studied the activation behavior of Lao72Sr018Mn03 cathode after treatment of the LSM coating with diluted hydrochloric acid (HC1) solution. The etched solution... 

After the mechanical pre-treatment, the electrode can be subjected to a chemical and/or electrochemical pre-treatement. Chemical treatment consists mainly of etching of a few layers of the metal, including possible contaminants. A well-known etching solution for gold is the so-called piranha solution. Other reported solutions are kali, which is a concentrated KOH solution to remove fats and oils and etch off a layer of platinum. 

The etch rate of CVD oxide is generally higher than that of thermal oxide as shown in Eig. 4.2 and Eig. 4.19." It is strongly affected by the formation conditions as, for example, shown in Eig. 4.20. " It has been found that the etch rate of the LPCVD Si02 oxide in diluted HP solution is lower than conventional CVD film. In addition to the formation conditions, the etch rate of CVD oxides is determined by (I) type and concentration of the dopant, (2) condition of the postdeposition treatment, and (3) composition of etching solution. 

Etching solutions can be purchased from a number of sources. They include Fluoro Etch by Acton Corp. and Tetra-Etch by W. L. Gore Associates. Some companies, such as Acton Corp., provide surface treatment service. Operational safety and waste disposal are two issues concerning parties that deal with etching solutions. 

Whitesides and coworkers developed a procedure to estimate the density of defects in gold-thiol monolayers. The monolayer surface is exposed to the gold-etching solution, the pits obtained are transferred into pits on the Si surface through further chemical treatment and the number of pits per unit area counted. Long-chain alkanethiolate monolayers prepared by the standard technique show pit densities of ca 100 pits mm . The number of pits sharply increase if the gold surface is stored for a long time in air prior to monolayer deposition . 

Detailed recipes for pre-treatment of copper, (which are also suitable for some copper alloys) are given in Refs. [1-4]. The simplest treatment consists of abrasion (see Abrasion treatment) with emery cloth followed by Degreasing in a chlorinated hydrocarbon solvent. Most of the treatments recommend a more elaborate routine of (1) degrease (2) etch and (3) dry. Etching solutions for use at ambient temperature include iron(III) chloride in either nitric or hydrochloric acid. Immersion for between 1 and 3 min is advised. Ammonium persulphate solution (1 3 or 1 4 parts by weight) is also used at room temperature perhaps for times as short as 30 s. ... 

Treatment of ammoniacal etching solutions by SLM-based technique... 

Treatment of etching solutions [29]. Etching involves the dissolution of metal, typically copper, from the board by an etching/oxida-tion solution. The effectiveness of the etchant solution progressively falls due to the consumption of the etchant by the reaction, which in the case of a copper chloride etchant is ... 

Liquid etchants can be used for chenucal modification or dissolving surface contamination. Etchants effectively treat irregularly shaped objects that are difficult to treat by other adhesion-promoting processes such as corona or flame treatment. A number of etching solutions and procedures have been developed for specific polymeric surfaces. The choice of the liquid etchant depends on the polymers. Polyolefins are usually treated by oxidizing acids such as chromic, sulfuric, nitric, or mixtures of these. Fluorocarbons are usually treated by sodium-napthalene etching solution. 

The oldest treatment is an etching process in highly concentrated chromic-sulfuric acid with a temperature near 80°C. Highest adhesional strength between PP and, for example, a two-component epoxy (EP) adhesive is reached after etching times between 120 and 240 s. The recipe of the etching solution is 5078 parts of sulfuric add (density 1.82g/ml), 120 parts demineralized water and 75 parts potassium dichromate. 

Today, such a process is not recommended because the etching solution contains chromium VI ions which are carcinogenic. Beside this fact, the etching process must be followed by very intensive rinsing and drying processes. The effectiveness of the surface treatment, on the other hand, is very good. 

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