CN110186900B

CN110186900B - Test pool for testing metal corrosion by coupling Raman spectrum and design method thereof

Info

Publication number: CN110186900B
Application number: CN201910500977.2A
Authority: CN
Inventors: 齐建涛; 汪振文; 刘伟; 陈梦瑶; 胡爽飞; 丁一航
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2019-06-11
Filing date: 2019-06-11
Publication date: 2022-05-27
Anticipated expiration: 2039-06-11
Also published as: CN110186900A

Abstract

The invention discloses a test cell for testing metal corrosion by coupling Raman spectrum and a design method thereof. The testing process can overcome the influence of the environmental change of the traditional static corrosion solution on the corrosion mechanism along with the time extension of the corrosion solution, and can expand the accuracy of the multi-technology coupling corrosion testing process. It is worth noting that the novel corrosion tank is provided with a trapezoidal concave structure close to the center of the upper half part observed by the objective lens, so that the effective observation distance between the objective lens and the metal to be detected is favorably enlarged, the magnification is improved, and more local corrosion information is provided. In addition, the whole corrosion pool is light and economic in design, and 3D printing forming can be achieved.

Description

Test pool for testing metal corrosion by coupling Raman spectrum and design method thereof

Technical Field

The invention relates to a metal corrosion test pool, in particular to a test pool suitable for testing metal corrosion by coupling Raman spectroscopy and a design method thereof.

Background

Electrochemical and physical information of local corrosion micro-areas are important parameters for representing metal corrosion rate, but the test precision is limited due to the irregularity of local corrosion areas and the limitation of mesoscopic size. The Raman spectrum technology is a technology which can be used for analyzing information such as electrochemical components and space structures of molecular scales and has the characteristics of more accommodated information, simple sample pretreatment, small water interference, non-invasion and the like. The method is widely applied to medicine detection, drug detection, cultural relic research, food detection and battery electrode material research. In recent years, multidisciplinary fusion and multi-technology coupled research methods have received increasing attention. In the research of local corrosion of metal, the corrosion detection of coupled Raman spectrum and optical microscope has also made new progress. Ramya et al measured the change of chemical composition of the film layer with reaction time during pitting by in situ Raman. (S.Ramya, et al. applied Surface Science,2018,428: 1106-. However, the raman etching cell proposed by them takes the form of a built-in etching solution, and oxygen is continuously consumed or even consumed during a long-term reaction. This environment is not compatible with the true metal corrosion environment, and is not suitable for the study of long-term metal corrosion mechanism.

Disclosure of Invention

The invention provides a novel metal corrosion tank and a design method thereof, aiming at overcoming the defects that the solution of the corrosion tank in the traditional corrosion tank is static and changes along with time and realizing the reality and reliability of multi-technology coupling research on metal corrosion. The structure design of the traditional corrosion tank is changed by adding a corrosion solution inlet and outlet, a flow passage in the corrosion tank, gaskets on the upper part and the lower part of the corrosion tank, sealing connection of the corrosion tank and other parts, and the accuracy of the multi-technology coupling research on metal corrosion behavior is further ensured by matching with the peristaltic pump and pipeline design.

In order to achieve the purpose, the invention adopts the following technical scheme: an operator utilizes a peristaltic pump with constant volume and fixed time to pump out the corrosion solution from the beaker and convey the corrosion solution to a novel corrosion tank placed on a Raman test platform, so that dynamic corrosion occurs, a Raman spectrum test microscope above the corrosion tank captures spectrum information of a corrosion product, and the corrosion solution is output to a terminal beaker from an outlet of the corrosion tank.

Wherein, the length x width x height of the whole appearance of the upper half part (2) of the corrosion tank is 70x 50x 10 mm; the central observation area is of a trapezoidal concave structure, the depth of the central observation area is 4mm, the length x width of the top part is 18.5x 9.5mm, and the length x width of the bottom part is 14 x 8 mm; in addition, the left side and the right side of the upper part are respectively provided with a circular through hole (r) with the diameter of 5mm in a transverse symmetrical mode, and the length of each through hole is 19 mm; on the basis of the through hole, a small hole (II) with the diameter x and the length x of 3x 4.5mm is continuously drilled inwards; the periphery of the frame is longitudinally provided with 8 bolt holes with the diameter of 4 mm; it is worth noting that a groove and a flow channel are reserved on the lower end face, the groove is 18 mm long, the radius of the semi-circle at the two ends is 5mm, and the width x depth of the groove is 1x 0.7 mm; semicircular holes (r) with the radius x and the depth of 3x 3mm are symmetrically distributed on two sides of the central observation area, and a square hole (c) with the length x, the width x and the depth of 1x 1x 1mm is continuously drilled upwards in the semicircular holes, so that the semicircular holes of the lower end surface and the through holes which are transversely distributed are communicated with each other to form a flow channel.

In contrast, the lower part (3) of the cell is etched. The length, width and height of the whole appearance are 70x 50x 12 mm; and 8 bolt holes with the diameter of 4mm are longitudinally arranged on the periphery of the support.

The invention has the following advantages:

(1) the metal corrosion pool facilitating the solution flow can simulate the metal corrosion mechanism in the environments of long-time corrosion, different fluid states and the like, and the application range and the accuracy of the multi-technology coupling test technology are expanded;

(2) the metal corrosion pool facilitating the flow of the solution has a trapezoidal concave structure at the upper half part, so that the effective observation distance between the objective lens and the metal to be detected can be enlarged, the magnification is improved, and more local corrosion information is provided;

(3) and 3D printing can be realized by the metal corrosion pool with flowing solution, and the printing device is efficient in forming and economical in cost.

Drawings

FIG. 1 is a flow chart of coupled Raman spectroscopy for testing metal corrosion.

FIG. 2 is a part view of the upper part of the corrosion cell, wherein FIG. 2a is a CAD two-dimensional view of the upper half; FIG. 2b is a two-dimensional view of the lower end surface of the upper half; fig. 2c is a cross-sectional view of the lower end face of the upper part at the transverse axis of symmetry (corresponding to position a-a in fig. 2 b).

Fig. 3 is a part view of the lower part of the corrosion cell, wherein fig. 3a and 3b are CAD two-dimensional views of the lower half of the corrosion cell.

FIG. 4 is an assembled view of the corrosion cell.

Fig. 5 is a table of sizes corresponding to the holes in fig. 2 c.

In the figure: R2.5-M4 bolt radius, 2.5 mm; r3-radius of semicircular hole of flow channel, 3 mm; r5-the inner radius of the groove semicircle, 5 mm; r6-groove semicircle outer radius, 6mm

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

3D printing a metal corrosion pool according to FIGS. 2 and 3;

according to fig. 4, an ultra-thin cover glass (0.1mm thick) is first glued to the bottom of the step structure of the central observation area of the upper half of the corrosion cell by means of 502 super glue; then, filling the grooves in the upper half part by using gaskets (the diameter and the thickness are respectively 16mm and 1mm), further placing a metal sheet to be tested in the middle of a corrosion tank, and finally symmetrically tightening by using 8M 4 bolts to connect an upper corrosion tank and a lower corrosion tank;

and (3) combining the flow chart of the whole testing device built by the method shown in the figure 1.

The specific implementation mode of the coupled Raman spectrum for testing the metal corrosion is as follows: an operator utilizes a peristaltic pump with constant volume and fixed time to pump out the corrosion solution from the beaker and convey the corrosion solution to a novel corrosion tank placed on a Raman test platform, so that dynamic corrosion occurs, a Raman spectrum test microscope above the corrosion tank captures spectrum information of a corrosion product, and the corrosion solution is output to a terminal beaker from an outlet of the corrosion tank.

Claims

1. A corrosion cell for coupled Raman spectroscopy to test metal corrosion is characterized in that:

the corrosion tank is divided into an upper part and a lower part which are detachable, a solution inlet and a solution outlet which are matched with a peristaltic pump and a hose for size and flow conversion are arranged on the left side and the right side of the upper half part, a flow channel is arranged in the upper half part, a trapezoidal concave structure is arranged in a central observation area of the corrosion tank, the bottom of the corrosion tank is sealed by using an ultrathin cover glass, in addition, a groove and a gasket structure are arranged on the lower end surface of the upper half part, the upper end surface of the lower half part of the corrosion tank is a plane and is used for placing a metal sample and maintaining the level of the upper connecting end surface and the lower connecting end surface; the lower end surface of the lower half part of the corrosion tank is of a cross structure, so that the stability of the corrosion tank placed on the observation platform is ensured;

the design method comprises the following steps: a. the central observation area of the upper half part is of a trapezoidal concave structure, the depth of the central observation area is 4mm, the length multiplied by the width of the top part is 18.5 multiplied by 9.5mm, and the length multiplied by the width of the bottom part is 14 multiplied by 8 mm; adhering the ultrathin cover glass to the bottom of the step structure of the central observation area of the upper half part of the corrosion tank by using 502 super glue to seal the bottom of the step, and ensuring that the objective lens observes the aqueous solution in the metal corrosion process to be a plane; in addition, the length multiplied by the width multiplied by the height of the whole appearance of the upper half part of the corrosion tank is 70 multiplied by 50 multiplied by 10 mm; the left side and the right side of the upper part are transversely symmetrically provided with a circular through hole with the diameter of 5mm respectively, and the length of the through hole is 19 mm; on the basis of the through hole, a small hole with the diameter multiplied by the length of 3 multiplied by 4.5mm is continuously punched inwards; the periphery of the frame is longitudinally provided with 8 bolt holes with the diameter of 4 mm; it is worth noting that the lower end face of the upper half part is provided with a groove and a flow channel, the groove is 18 mm long, the radius of the semicircle at the two ends is 5mm, the width multiplied by the depth of the groove is 1 multiplied by 0.7mm, the embedded gasket with the diameter multiplied by the thickness of 16 multiplied by 1mm can realize the flowing of ultrathin solution, and the sealing performance of the upper corrosion tank and the lower corrosion tank is good; semicircular holes with the radius multiplied by the depth of 3 multiplied by 3mm are symmetrically distributed on the lower end surface of the upper half part on two sides of the central observation area, a square hole with the length multiplied by the width multiplied by the depth of 1 multiplied by 1mm is continuously drilled in the hole, thus ensuring that the semicircular holes on the lower end surface of the upper half part are communicated with the through holes which are transversely distributed to form a flow passage;

b. the length multiplied by the width multiplied by the height of the whole appearance of the lower half part of the corrosion tank is 70 multiplied by 50 multiplied by 12mm, and the periphery is longitudinally provided with 8 bolt holes with the diameter of 4 mm; the upper end surface of the lower half part is a plane, and four corners of the lower end surface are of a cube structure of 17 multiplied by 17mm, namely a protruding cross structure with the thickness of 3mm, so that the stability of the corrosion tank on the observation platform is ensured;

c. the connecting parts are connected by 8M 8 bolts which are symmetrically distributed, so that the integral sealing effect is ensured;

d. the corrosion tank can realize the purpose of multi-technology coupling test on metal corrosion by matching with a peristaltic pump and a pipeline system.

2. The corrosion cell for testing metal corrosion by coupling Raman spectroscopy according to claim 1, wherein a peristaltic pump with a constant volume and a constant time is used in the whole testing process, solutions before and after corrosion are placed in beakers at the first end and the last end, and the Raman spectroscopy can directly detect metal in a central observation area of the corrosion cell.

3. The corrosion cell for coupled raman spectroscopy testing of metal corrosion of claim 1, wherein optical microscopes with different magnifications can monitor and record the change of metal surface morphology during corrosion and raman spectroscopy can directly detect the metal in the central observation area of the corrosion cell, thereby providing multi-scale corrosion information of the metal corrosion morphology changing with corrosion time, the raman spectroscopy of corrosion products and the change of corrosion solution components.