Method for plating copper on rock sample for scanning electron microscope

Technical Field

The invention relates to a scanning electron microscope method for copper plating of rock sample. Belongs to the technical field of petroleum geology.

Background Art

At present, in the scanning electron microscope analysis rock sample, rock samples showed that the need for plating a layer of conductive material.

Gold as a film coating material, to its chemical properties are stable, good conductivity, low melting point, high secondary electron emissivity and widely used. Because the scanning electron microscope technology can be very clearly observe the micro the rock structure and composition, therefore, scanning electron microscope technology in the field of oil exploration and development of the large-scale application. Gold is a noble metal, gold as a film coating material in costs, supply, transport and store, there are a lot of inconvenience.

Content of the invention

In order to overcome the deficiency of the prior art, the present invention provides a scanning electron microscope method for copper plating of rock sample, relates to a scanning electron microscope in the rock sample for microscopic analysis.

Scanning electron microscope method for copper plating of rock sample, including:

Step 1:

A. The choice of the rock sample. Generally not exceeding the size of the scanning electron microscope (φ 5-10mm) sample pile. The rock sample with special requirements can be strengthened, but also according to the size of the rock the sample.

B. Must be selected fresh section of rock sample, a stratification of the rock samples to vertical stratification selecting the direction of, the surface of the rock sample must be clean and dry, and not in a vacuum phenomenon of generating the bleeding and dehydration, vacuum or avoid distortion caused by analysis.

Step 2:

Rock sample treatment: of rock sample according to the analysis purposes, pre-processing, general according to the following program to carry out treatment: oil washing → dyeworks → purifying → drying.

Step 3:

Rock pile on the sample: plaquelike rock sample is the pile of the latex layer, powder bonding double-sided adhesive tape for rock sample.

Step 4:

Rock sample plated film: the rock sample is put into the electron microscope sample rock sample coating machine, evaporation electrode basket is placed in the copper, to be rock sample is pumped into the high vacuum of the vacuum chamber, open evaporation electrode, coating with current, to be rock samples after the surface plating layer meets the requirement, of rock sample plated film can be accomplished.

The vacuum sample chamber then, the rock samples plated out, is observed under scanning electron microscope. Copper plating the thickness of a film plated with gold plating, time and rock sample table for the actual operation the angle of the technical differences existing in the process. The control of the thickness of the copper plating ≤ 60 nm, the amount of copper material consumption 0.3 g left and right; a time control in the 100S; coating the rock sample stage inclination angle 20-40 °, and 360° continuous rotation; for cementing dense, smooth surface coating film b times rock sample; cementing loose, the rough surface of the plated film three times rock sample. The creation of these is that this method of the invention point, it is also necessary to protect the contents of the Patent.

The rock samples after the film plating, in the microscope observation:

Still alternative still between the commonly used coating effectiveness analysis comparison;

The thickness of the plating layer effect analysis comparison;

Different types of rock sample analysis and contrast coating effect.

In the above-mentioned analysis, on the basis of the comparison, determining the corresponding coating conditions and viewing conditions.

The advantage of this invention is the rock sample scanning electron microscope of the present invention the method for copper plating, for the first time in the scanning electron microscope using metal copper alternative precious metal gold plating film; can meet the needs of the different rock types; the invention has saved the coating material purchase, the purchase of the material at the same time provides the convenience and management.

Mode of execution

Obviously, on the basis of the technical personnel in the field of the invention the aim of the many modifications and changes in the scope of protection of this invention.

Embodiment 1:a scanning electron microscope method for copper plating of rock sample, when the coating, to the compact rock sample only secondary plating film, the thickness of the plating layer of the 30 nm -40 nm, totally meet the analysis requirements; the loose rock sample, of oil-bearing rock sample, surface irregularity powder of rock sample and three times the rock samples need to be coated, the thickness of the plating layer is 50 nm -60 nm.

1. The of the instrument:

DMX-220A-shaped vacuum coater;

Evaporation electrode: 2 a;

Vacuum degree: the highest can be up to 7 × 10-2Pa;

Sample table: 360 ° rotating 120° inclined;

Evaporation current: 0-60A;

The evaporation source distance rock sample: 8 cm;

British cambridge S-360-type scanning electron microscope;

Resolution: 4 nm;

Magnification: 5-30 million times continuously adjustable;

Accelerating voltage: 0.2kv -30kv continuously adjustable;

Sample table: x, y shaft mobile 100 mm;

Z-axis movement 70 mm;

Rotating 360° inclined 0-90 °;

With the Image memory and processing function.

2. Coating material:

As a film coating material must possess better conductivity, thermal conductivity, low melting point and boiling point, is easy to be evaporated, with higher secondary electron emissivity, good chemical stability, fine the particle structure of the reservoir and such basic conditions. Selecting the copper as an experimental coating material. Gold and copper of the main physical properties in table 1.

Table 1 physical properties of   different coating material

3. the key point of plated film:

Copper plating film of gold plating step of the step of the conventional and the same.

The quality of the coating film layer is the key scanning electron microscope analysis. The operation of the need for skilled techniques, according to the nature and still the nature of the rock sample, to determine a proper coating thickness.

Crucial point in the copper plating film is as follows:

4. Development of experimental programme:

Experimental rock samples mainly to junggar basin, Tarim basin portions selected from. Choose different clastic rock cementation degree, mudstone, carbonate rock, rock sample containing oil, and rock samples of cheese rock sample in (table 2).

Table 2   experimental rock sample schedule

The above-mentioned rock sample are respectively plated with gold and copper plating, and scanning electron microscope analysis of the experiment.

5. experimental method:

Rock sample preparation:

All experimental rock samples the conventional processing-pile-plated film. The coating thickness of rock sample in the general control 20-60nm between. According to experience formula Mueller, each coated with a disk of rock sample (34 block), with gold 0.4g -0.6g; each coated with a disk of rock sample (34 block), with copper 0.30 g. The cementation dense, smooth surface two times rock sample general plating; the cementation loose, the rough surface of the rock samples plating three times required. Rock the inclination angle of the sample table should be controlled in 20-40 °, and 360° rotation. Under the above-mentioned condition, is completed within a specified period of time to melt the whole process of evaporation, the rock sample surface to obtain uniform and continuous coating.

Contrast experiment content:

The experimental coating rock sample observation with the microscope, its observation content is:

1) gold plating of rock sample scanning electron microscope analysis;

2) copper plating of rock sample scanning electron microscope analysis;

3) analysis of effect compared with the thickness of the plated layer;

4) Image quality determination.

Gold plating experiment analysis effect: can meet the requirements of experiments of the scanning electron microscope.

Copper plating experiment analysis effect: the dense rock sample, continuous coating to observe under the scanning electron microscope, the basic no-load electricity phenomenon, plated film effects are better. Loose rock sample is partially charged, by means of an Image processing analysis requirements can be satisfied. Oil-bearing rock sample plated film effect is poor, the required 5kv -10kv the accelerating voltage gastrojejunocolic, Image capture can be carried out, obtaining better picture. The oil-bearing rock sample saturated, because of forming the oil film is difficult to distinguish fine clay mineral, but the porosity and selfgenerated mineral observation, since the resolution and the magnification requirement is not high, can be used in reduced acceleration voltage phenomenon of the method of charge reduction, analysis requirements can be met.

Rock sample in the secondary coating analysis requirements can be met.

After copper plating three times various rock sample effect of observation and Image quality is improved to a large extent, can meet the analysis requirements.

When a film plated, as long as the lithology of rock samples according to different control different the thickness of the plating layer, that can meet the requirements of experiments of the scanning electron microscope.

The dense rock sample need for secondary plating film, the thickness of the plating layer of the 30 nm -40 nm, can meet the analysis requirements; the loose rock sample, sample of oil-bearing rock, powder of rock sample and irregular surface the rock samples need to be three coating, the thickness of the plating layer is 50 nm -60 nm, can meet the analysis requirements.

The copper plating in the rock sample after four months, as the repeated observation, the coating effect is found with the initial plated film result. Proven metal copper can replace expensive gold as various types of scanning electron microscope in the future the main rock sample film coating material.

Various types of rock samples through the copper plating film material experimental contrast analysis, copper with a suitable melting point, boiling point, evaporating humidity, copper in the heating evaporation is not easy to be falling off from the tungsten filament, general rock sample to obtain a continuous coating.

Copper metal materials to substitute for gold as a film coating material, consideration from the sources, gold is a noble metal, is not easy to be purchased, the metal copper which belongs to the conventional material, is easy to purchase, easy to store.

The experiment carried out in succession 182 the analysis of the sample in rocks, cameraphone 700 multi-sheet, and the coating of the various rock samples photo effect, achieved good experimental effect.

Scanning electron microscope method for copper plating of rock sample since 1993 year began to use, successively to dzungaria, Tarim basin, basin turpan kazakh areas of the clastic rock and, mudstone, carbonate, oil-containing rock sample, rock sample of cheese, rock sample in a scanning electron microscope analysis, annual 1200 blocks of rock sample analytical tasks, to clients provides consistent with the actual data information. At the same time, very significant economic benefits.

As mentioned above, the embodiment of this invention detailed description of the, however, as long as substantially not from the point of the invention there can be many and the effect of the deformation, to the field of technical personnel is obvious. Therefore, the deformation of this embodiment also are all comprised in the scope of protection of this invention.