TWI507682B - Evaluation method of corrosion resistance of nickel plate - Google Patents

Description

Corrosion resistance evaluation method of nickel plate

The invention relates to a method for evaluating the corrosion resistance of a nickel plate to a high-temperature molten ammonium hydrogen fluoride, in particular to an anodic polarization curve of a nickel plate obtained by high-temperature melting ammonium hydrogen fluoride by linear sweep voltammetry, and by the anode pole The total curve of the nickel plate was calculated, thereby quickly and quantitatively evaluating the corrosion resistance of the nickel plate in the high temperature molten ammonium hydrogen fluoride.

Nitrogen trifluoride (NF ₃ ) is widely used in semiconductor and thin film solar cell processes and as an etchant and cleaner. Nitrogen trifluoride is obtained by using a nickel plate as an anode and performing an electrolysis process on molten ammonium fluoride (formula: NH ₄ ‧ xHF). However, since the nickel plate is susceptible to fluorine corrosion during electrolysis, the electrolysis efficiency is poor, and the nickel plate itself is also lost. Therefore, in order to make the nickel plate have a low loss rate under long-term use, the material selection and composition design of the nickel plate has become a widely studied subject, in addition to providing an evaluation of the corrosion resistance of the nickel plate. The method to understand the performance of the nickel plate.

At present, the method for evaluating the corrosion resistance of a nickel plate to a high-temperature molten ammonium hydrogen fluoride is to immerse the nickel plate in a high-temperature molten ammonium hydrogen fluoride for more than 20 days, and calculate the weight difference of the nickel plate before and after the soaking, thereby evaluating Corrosion resistance of nickel plate to high temperature molten ammonium hydrogen fluoride. The evaluation method requires at least 20 The day can be completed, so that the nickel plate has obvious weight difference before immersion and after immersion, thereby reducing the error caused by the measurement and increasing the accuracy of the evaluation, and there are shortcomings that are too long, which is not conducive to the rapid Detect shipment requirements. From the above description, it can be seen that it is helpful for those skilled in the art to provide a method for more quickly and quantitatively evaluating the corrosion resistance of a nickel plate in a high temperature molten state of ammonium hydrogen fluoride in order to understand the performance of the nickel plate. .

Accordingly, it is an object of the present invention to provide a method for evaluating the corrosion resistance of a nickel plate. The corrosion resistance evaluation method of the nickel plate can more quickly and quantitatively evaluate the corrosion resistance of the nickel plate in the molten state of ammonium hydrogen fluoride.

Therefore, the method for evaluating the corrosion resistance of the nickel plate of the present invention comprises the following steps: a preparation step comprising: providing a nickel plate and a molten ammonium hydrogen fluoride; and a measuring step comprising: using the nickel plate as a working electrode and placing the same on the nickel plate In the molten ammonium bifluoride, and providing a certain potential scanning rate and a potential scanning range, and measuring according to Linear Sweep Voltammetry (LSV), a current-potential anodic polarization curve is obtained ( Anodic polarization curves), wherein the anodic polarization curve has two anode peaks; a calculation step comprising: calculating the unit area charge amount of the two anode peaks of the anodic polarization curve by using formula (i), respectively, to obtain Q ₁ and Q ₂ Q _x =∫ I×dt (i)

Further, Q ₁ and Q ₂ are substituted into formula (ii) to calculate the nickel reaction amount of the two anode peaks to obtain m ₁ and m ₂ , and m ₁ and m ₂ are added to obtain a total loss of nickel plate m. m _x =WQ _x /Fn _x (ii)

Where I is the current per unit area, t is the distance of the potential scanning range divided by the potential scanning rate, W is the atomic weight of nickel, F is the Faraday constant, n _x is the number of reactive electrons of the anode peak, and Q _x is Q ₁ Or Q ₂ , m _x represents m ₁ or m ₂ , n _x represents n ₁ or n ₂ ; and an evaluation step comprising: evaluating the corrosion resistance of the nickel plate in the molten ammonium hydrogen fluoride from the total loss of the nickel plate .

The effect of the invention is that the anodic polarization curve of the nickel plate in the molten ammonium hydrogen fluoride is obtained by linear sweep voltammetry, and the unit area charge amount Q _x of the two anode peaks is calculated respectively, and the unit area charge is utilized. after the calculated amount Q _x, respectively, the two peaks of the nickel anode reaction amount m _x, is obtained by adding the total loss of nickel plate m, the total loss of the nickel plate by an amount m evaluated the molten nickel plate in ammonium bifluoride Corrosion resistance. The evaluation method of the present invention can more quickly and quantitatively evaluate the corrosion resistance of the nickel plate in the molten ammonium hydrogen fluoride.

The details of the present invention will now be described in detail. The linear sweep voltammetry is carried out in a conventional manner, and is not particularly limited, and an appropriate electrode can be selected as needed.

Preferably, the anodic polarization curve is a polarization curve in the active dissolution zone.

The type and material of the nickel plate are not particularly limited, and a nickel plate used in the field of electrolytically melting ammonium hydrogen fluoride to produce nitrogen trifluoride can be used. The present invention is applied to the nickel plate such as, but not limited to, a pure nickel substrate or a nickel composite substrate. The nickel composite substrate is, for example but not limited to, a nickel-copper composite substrate, a nickel-cobalt complex A substrate, or a nickel-aluminum composite substrate or the like.

Preferably, the nickel plate has a nickel content of 99% by weight or more, which means that the individual content of each of the other components (for example, copper, cobalt, aluminum, manganese, magnesium, etc.) contained in the nickel plate is low, so that it is reasonable The anodic polarization curve is considered to be all contributed by the oxidation reaction of nickel. More specifically, the two anode peaks are respectively contributed by Ni + 2F ^- → NiF ₂ + 2e ^- and Ni + 3F ^- → NiF ₃ + 3e ^- .

Preferably, the corrosion resistance evaluation method of the nickel plate further comprises a curve fitting step before the calculating step, the curve fitting step is to perform curve fitting of the two anode peaks by using a Gaussian distribution to obtain two The fitted anode peaks are used, and the unit area charge values of the two fitted anode peaks are calculated using the equation (i), respectively.

Preferably, the molten ammonium hydrogen fluoride has a temperature in the range of 80 ° C to 120 ° C.

Preferably, the potential sweep range is from -250 mV to 6V.

Preferably, the potential scanning rate is selected from the range of 10 mV/s to 100 mV/s.

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is an anodic polarization graph illustrating the corrosion resistance evaluation methods of the nickel plates of Examples 1 to 3. The anodic polarization curve; and FIG. 2 is a partial enlarged view of an anodic polarization curve illustrating the anodic polarization curves obtained by the corrosion resistance evaluation methods of the nickel plates of Examples 1 to 3.

The present invention will be further illustrated by the following examples, but it should be understood that this embodiment is intended to be illustrative only and not to be construed as limiting.

<Example>

[Example 1] Evaluation method of corrosion resistance of nickel plate

1. Electrolyte: molten ammonium hydrogen fluoride (NH ₄ F‧2HF) at 100 °C.

2. Anode: Nickel plate A (nickel content 99.762wt%)

3. Cathode: Platinum

4. Scanning method: linear sweep voltammetry.

5. Potential scanning range: -250mV to 6V.

6. Scan rate: 10 mV/s.

7. Number of scans: 1 time.

Using a potentiostat (manufacturer: BioLogic, model: EC-LAB series, model VSP), using the operating software built into the potentiostat (BioLogic EC-LAB software) with linear sweep voltammetry Obtaining a current-potential anodic polarization curve, wherein the anodic polarization curve has two anode peaks, respectively contributed by Ni+2F ^- →NiF ₂ +2e ^- and Ni+3F ^- →NiF ₃ +3e ^- See Figure 1 and Figure 2.

The two anode peaks were then curve fitted with a Gaussian distribution using the Origin 9 software to obtain two fitted anode peaks. Next, using the Origin 9 software, calculate the unit area charge amounts Q ₁ and Q ₂ (unit: mA.s/cm ² ) of the two fitted anode peaks using equation (i), and then Q ₁ and Q. ₂ Substituting formula (ii) Calculate the nickel reaction amounts m ₁ and m ₂ of the two fitted anode peaks respectively, and add m ₁ and m ₂ to obtain the total loss amount m of the nickel plate A.

[Examples 2 and 3] Evaluation method of corrosion resistance of nickel plate

Examples 2 and 3 were carried out in the same manner as in Example 1 except that the kind of the anode was changed. Example 2 was a nickel plate B (manufacturer: medium steel, nickel content: 99.82 wt%), and Example 3 was a nickel plate C (manufacturer: medium steel, nickel content: 99.9 wt%).

[Comparative Example 1] Evaluation method of corrosion resistance of nickel plate

The nickel plate A was immersed in molten ammonium hydrogen fluoride at 100 ° C for 20 days, and taken out, and the total loss of the nickel plate before and after immersion for 20 days of the nickel plate A was calculated.

[Comparative Examples 2 and 3] Evaluation method of corrosion resistance of nickel plate

Comparative Examples 2 and 3 were carried out in the same manner as in Comparative Example 1, except that the type of the nickel plate was changed. Comparative Example 2 uses nickel plate B, and Comparative Example 3 uses nickel plate C.

Referring to the results of Table 1, the total loss of the nickel plate obtained by the evaluation methods of Examples 1 to 3 shows that the corrosion resistance of the molten aluminum fluoride of the nickel plate A, the nickel plate B, and the nickel plate C at 100 ° C is excellent to poor. The order is: nickel plate C, nickel plate B, nickel plate A; the total loss of nickel plate obtained by the evaluation methods of Comparative Examples 1 to 3, it is known that the corrosion resistance of molten ammonium hydrogen fluoride at 100 ° C is superior to poor : Nickel plate C, nickel plate B, nickel plate A. Therefore, the tendency of the total loss amount of the nickel plate obtained by the evaluation methods of Examples 1 to 3 can be aligned with the tendency of the total loss amount of the nickel plate obtained by the evaluation methods of Comparative Examples 1 to 3, whereby it can be seen that the evaluation method of the present invention can be used In place of the conventional evaluation method, the evaluation method of the present invention can more quickly evaluate the corrosion resistance of the nickel plate in the molten ammonium hydrogen fluoride compared to the conventional evaluation method.

In summary, the anodic polarization curve of the nickel plate in the molten ammonium hydrogen fluoride is obtained by linear sweep voltammetry, the total loss m of the nickel plate is calculated, and the total loss m of the nickel plate is evaluated. Corrosion resistance of nickel plate in the molten ammonium hydrogen fluoride. The evaluation method of the present invention can more quickly and quantitatively evaluate the corrosion resistance of the nickel plate in the molten ammonium hydrogen fluoride, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (6)

A method for evaluating corrosion resistance of a nickel plate comprises the following steps: a preparation step comprising: providing a nickel plate and a molten ammonium hydrogen fluoride; a measuring step of using the nickel plate as an anode and placing the molten ammonium hydrogen fluoride And providing a certain value of the potential scanning rate and a potential scanning range, and measuring according to linear sweep voltammetry to obtain a current-potential anodic polarization curve, wherein the anodic polarization curve comprises two anode peaks; a curve fitting step of performing a curve fitting of the two anode peaks by using a Gaussian distribution to obtain two fitted anode peaks, and calculating the units of the two fitted anode peaks by using equation (i) Area charge value; Q _x = ʃI × dt Equation (i) A calculation step, using equation (i) to calculate the unit area charge of the two anode peaks of the anodic polarization curve, respectively, to obtain Q ₁ and Q ₂ , and then Substituting Q ₁ and Q ₂ into equation (ii) to calculate the nickel reaction amount of the two anode peaks to obtain m ₁ and m ₂ , and adding m ₁ and m ₂ to obtain a total loss of nickel plate m, m _x = WQ _x / Fn _x formula (ii) where, I is current per unit area, t The pitch of the potential sweep range divided by the potential sweep rate, W is the atomic weight of nickel, F is the Faraday constant, n is a number of reaction electrons of the anodic peak, Q _x represents Q ₁ or Q _2, m _x m ₁ or m ₂ represents , n _x represents n ₁ or n ₂ ; and an evaluation step of evaluating the corrosion resistance of the nickel plate in the molten ammonium hydrogen fluoride from the total loss m of the nickel plate. The method for evaluating corrosion resistance of a nickel plate according to claim 1, wherein the anodic polarization curve is a polarization curve in an active dissolution zone. The method for evaluating corrosion resistance of a nickel plate according to claim 1, wherein the nickel plate has a nickel content of 99% by weight or more. The method for evaluating the corrosion resistance of a nickel plate according to claim 1, wherein the molten ammonium hydrogen fluoride has a temperature in the range of 80 ° C to 120 ° C. The method for evaluating corrosion resistance of a nickel plate according to claim 1, wherein the potential scanning range is -250 mV to 6V. The method for evaluating corrosion resistance of a nickel plate according to claim 1, wherein the potential scanning rate is selected from the range of 10 mV/s to 100 mV/s.