SibNeoTech
Special materials
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Some physical specifications



Not all methods, the equipment and qualification allow to measure chemical purity of copper equally. Especially it concerns purity of 5N+ and above. Also, if physical characteristic is required, it will be impossible to tell precisely about it by means of only the chemical analysis, especially in cryogenics. Often direct measuring of characteristic is required.

Confirmation of quality of our product is the electrical conductivity which is independent of methods of the chemical analysis. Measuring was carried out with equipment appropriate to this problem.
Result is very high.

Also the Institute of Applied Physics of the Russian Academy of Science has made the measuring of reflectance of our sample at 0-300K. The result was also very high and close to calculations for theoretical copper .

ELECTRICAL  CONDUCTIVITY   104 - 105%  IACS



Representative sample was formed on the basis of the enough of chemical analyses describing fluctuations of a chemical compound of the BASIC quality of the experimental product. At sampling, the known various influence of various impurities on electric conductivity  also was considered. It was verified and was traced that also is an attribute of quality of sampling and measuring. The structure of ingots of samples is close or identical to other ingots.

Results of measuring of electrical conductivity and the presented statistical interval distribution of deviations of electric conductivity  enough correctly reflects the given characteristics of the experimental lots.
Electrical  conductivity  studies :
REFLECTANCE



There are given some data of researches of reflection loss and surface resistance of a copper mirror from our copper on some frequencies from temperature. In original articles our copper is mentioned as ultra-pure copper 99.999 or highly pure copper 99.999  (HP copper). At present under our grades, the investigated sample is super pure copper.

Reflectance studies (reflection loss) :
RRR ( R 293K  / R T )  and  THERMAL CONDUCTION  in cryogenics



For classical mass-produced copper, these characteristics are more or less investigated. The structure of mass-produced copper is usually close.

For purer copper the data are fragmentary, they can be very different and there are difficulties in comparing. Partly due to the fact that even laboratory samples with a purity of 5N5 and especially above, in accordance with generally accepted standards with a controlled impurity composition and crystal structure, are not easy to produce. Often, some general purity is reported, but not a specific chemical composition, or it is simply mentioned that they are measured and belong to the most pure and perfect samples. At low temperatures, the characteristics strongly depend on the impurities, on the degree of perfection of the crystal and other defects.

Below we present some data not for engineering calculations, but for a general picture. The data for Some Pure Copper 1, 2 and 3 are from sources trustworthy, and given the difficulty of measuring such quantities, it can be  accepted. Data for Some pure copper 1 is given for a very pure sample, the crystal structure is unknown. Some pure copper 2  was obtained in one of the research works as copper of 99.999% purity in the form of a single crystal with RRR 273K / 4.2K ~ 2000. Data for Some pure copper 3 are given for both the very pure and perfect sample with a residual resistance of 0.589 * 10 (-9) ohm * cm. Unfortunately, we have no data and clarity on how pure and perfect the samples are, that is, whether the characteristics of the Pure Copper 3 are the max for copper.
Temperature
К
4
8
10
15
20
25
30
40
99,95 - 99,97%, 100% IACS
М0б/М0 (RF), С10200 (USA),
Cu-OF/C110 (UK), C1020 (Japan)
RRR  ~
80-120
W /m*K ~
400
1000
1300
1800
2000
2000
1900
1500
min  99,99%,  101-102% IACS
М00б/М00 (RF), С10100 (USA),
Cu-OFE/C103 (UK), C1011 (Japan)
RRR  ~
200-300
W  /m*K ~
1200-2000
2500-4000
3500-4500
4500-5000
4500-5000
3500-4000
2600-3100
1500-1700
Special grade copper for use in cryogenics   :
CG-OFG, Hitachi Cable Ltd
RRR  ~
500
240-250
220
160
120
100
90
80
W /m*K ~
3000
5000
6500
7700
7000
6000
4000
2000
Some Pure Copper :
Some Pure Copper 1
RRR  ~
---
W /m*K ~
7500
12500
14000
12500
9000
7000
5500
2600
Some Pure Copper 2
RRR  ~
2100-2200
W /m*K ~
---
Produced Copper
Forecast
Some Pure Copper 3
RRR  ~
2900-3000
W /m*K ~
16200
24000
10800
PRODUCED COPPER

RRR and Thermal Conductivity are expected to be ~ 65-95% of the maximum possible for copper  (C10100: RRR ~ 200-300 or < 7-10%). The forecasted expectations of 65-95% max copper are justified and well founded. These characteristics of our copper are expected in the range Some pure copper 2 - Some pure copper 3.

From considerations arising from our Technology and some test results of our copper, we are sure that we have already produced a product close to Some pure copper 3. In any case, such results can be obtained.
P.S. RRR can be increased up to 1000 by annealing and "oxygenation" of copper with a purity of 99.99%, when the formation of oxides leads to a decrease in resistance. But this is not for very pure copper (impurities remain, increased oxygen content) with the ensuing consequences for other characteristics and properties: "hydrogen disease", reduction of plasticity, etc. For very pure copper 99.99999% (?) with RRR 2000 dissolving of oxygen 25 ppm leads to a decrease RRR to 50. Therefore, with copper 5N and higher under not standards must be handled, depending on the tasks: if RRR is needed, RRR may be worse than C10200 or worse, ect.
In some tasks, very high characteristics for RRR and Thermal Conductivity may be in conflict, in some cases vice versa. Super purety and perfect structure are not also a simultaneous requirement for some other tasks, but in some tasks are necessary. We proceed from the fact that for those tasks where maximum purity and structure are needed, with consequent characteristics and properties, when it is needed as such, then it is better that copper already exists, and we have produced it. Especially since it is not easy and it could be a limitation in the planning of tasks with use of such quality. In general, it is also useful for many existing tasks, but each must be looked at by evaluating the necessary parameters and benefits, and not just the mentioned characteristics.
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