ASTM E963-1995(2010) 6250 Standard Practice for Electrolytic Extraction of Phases from Ni and Ni-Fe Base Superalloys Using a Hydrochloric-Methanol Electrolyte《用盐酸甲烷电解质从镍和镍铁积超热合金中进行.pdf
《ASTM E963-1995(2010) 6250 Standard Practice for Electrolytic Extraction of Phases from Ni and Ni-Fe Base Superalloys Using a Hydrochloric-Methanol Electrolyte《用盐酸甲烷电解质从镍和镍铁积超热合金中进行.pdf》由会员分享,可在线阅读,更多相关《ASTM E963-1995(2010) 6250 Standard Practice for Electrolytic Extraction of Phases from Ni and Ni-Fe Base Superalloys Using a Hydrochloric-Methanol Electrolyte《用盐酸甲烷电解质从镍和镍铁积超热合金中进行.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: E963 95 (Reapproved 2010)Standard Practice forElectrolytic Extraction of Phases from Ni and Ni-Fe BaseSuperalloys Using a Hydrochloric-Methanol Electrolyte1This standard is issued under the fixed designation E963; the number immediately following the designation indicates the year ofori
2、ginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a procedure for the isolation ofcarbides,
3、 borides, TCP (topologically close-packed), and GCP(geometrically close-packed) phases (Note 1) in nickel andnickel-iron base gamma prime strengthened alloys. Contami-nation of the extracted residue by coarse matrix (gamma) orgamma prime particles, or both, reflects the condition of thealloy rather
4、than the techniques mentioned in this procedure.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of reg
5、ulatory limitations prior to use. (See 3.3.2.1 and4.1.1.)NOTE 1Ni3Ti (eta phase) has been found to be soluble in theelectrolyte for some alloys.2. Terminology2.1 Definitions:2.1.1 extraction celllaboratory apparatus consisting of abeaker to contain the electrolyte, a dc power supply, a noblemetal sh
6、eet or screen cathode and a noble metal wire basket orwire to affix to the sample (anode).2.1.2 geometrically close-packed (GCP) phasesprecipitated phases found in nickel-base alloys that have theform A3B, where B is a smaller atom than A. In superalloys,these are the common FCC Ni3(Al, Ti) or occas
7、ionally foundHCP Ni3Ti.2.1.3 topologically close-packed (TCP) phases precipi-tated phases in nickel-base alloys, characterized as composedof close-packed layers of atoms forming in basket weave netsaligned with the octahedral planes of the FCC g matrix. Thesegenerally detrimental phases appear as th
8、in plates, oftennucleating on grain-boundary carbides. TCP phases commonlyfound in nickel alloys are s, , and Laves.3. Significance and Use3.1 This practice can be used to extract carbides, borides,TCP and GCP phases, which can then be qualitatively orquantitatively analyzed by X-ray diffraction or
9、microanalysis.23.2 Careful control of parameters is necessary for reproduc-ible quantitative results. Within a given laboratory, such resultscan be obtained routinely; however, caution must be exercisedwhen comparing quantitative results from different laborato-ries.33.3 Comparable qualitative resul
10、ts can be obtained routinelyamong different laboratories using this procedure.34. Apparatus4.1 Cell or Container for Electrolyte A glass vessel ofabout 400-mL capacity is recommended. For the sample sizeand current density recommended later in this procedure,electrolysis can proceed up to about 4 h,
11、 and up to about4gofalloy can be dissolved in 250 mL of electrolyte withoutexceeding a metallic ion concentration of 16 g/L. Above thisconcentration, cathode plating has been observed to be morelikely to occur. A mechanism for cooling the electrolyte isrecommended. For example, an ice water bath or
12、water-jacketed cell may be used to keep the electrolyte between 0and 30C.4.2 CathodeMaterial must be inert during electrolysis.Tantalum and platinum sheet or mesh are known to meet thisrequirement. Use of a single wire is to be avoided, sincecathode surface area should be larger than that of sample.
13、Distance between sample and cathode should be as great aspossible, within the size of cell chosen. For example, a samplewith a surface area of 15 cm2should have no side closer than1.2 cm to the cathode. If the cell is cylindrical, as for the caseof a beaker or the upper part of a separatory funnel,
14、the cathodecould be curved to fit the inner cell wall to facilitate correctsample-cathode distance. The sample would then be centered1This practice is under the jurisdiction of ASTM Committee E04 on Metallog-raphy and is the direct responsibility of Subcommittee E04.11 on X-Ray andElectron Metallogr
15、aphy.Current edition approved April 1, 2010. Published May 2010. Originallyapproved in 1983. Last previous edition approved in 2004 as E963 95 (2004).DOI: 10.1520/E0963-95R10.2Donachie, M. J. Jr., and Kriege, O. H., “Phase Extraction and Analysis inSuperalloysSummary of Investigations by ASTM Commit
16、tee E-4 Task Group I,”Journal of Materials , Vol 7, 1972, pp. 269278.3Donachie, M. J. Jr., “Phase Extraction and Analysis in SuperalloysSecondSummary of Investigations by ASTM Subcommittee E04.91,” Journal of Testingand Evaluation, Vol 6, No. 3, 1978, pp. 189195.1Copyright ASTM International, 100 Ba
17、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.within the cell at the same height as the cathode. The cathodeneed not make a complete ring around the sample nor be morethan 5 cm high.4.3 AnodeThe sample must be suspended in the electro-lyte by a material that is inert
18、during electrolysis. Anodeconnection material should be cleaned to prevent any contami-nating material from falling into the cell. Good electricalcontact should be maintained between the sample wire and thepermanent anode wire from the dc power supply. Two methodsare found to be successful. Either m
19、ethod is subject todisconnection of the sample due to shrinkage, which puts alimit on the electrolysis time:4.3.1 Suspend the sample by platinum or platinum-rhodiumthermocouple wire (20 gauge) wrapped around it to form abasket. To avoid a shielding problem, the ratio of sample areacovered by the wir
20、e to the exposed sample area should besmall.4.3.1.1 Mechanically attach or spot weld the platinum orplatinum-rhodium thermocouple wire to the sample.4.3.2 If the weld is not immersed, non-inert wire may besubstituted; for example, chromel, nichrome, 300 series stain-less steel, etc. Stop-off lacquer
21、 should be used below themeniscus to maintain constant electrolyte level. This alsoeliminates formation of insoluble deposits immediately abovethe meniscus and prevents arcing.4.3.2.1 WarningCare must be taken to prevent arcingbetween anode and cathode which could ignite the methanol.4.4 Power Suppl
22、yA variable dc power supply capable ofproviding 0 to 5 V is needed to obtain currents from 0 to 1.2 Adepending on total surface area of the sample. For example, asample with total surface area of 15 cm2, electrolyzed at acurrent density of 0.1 A/cm2, requires:15 cm23 0.1 A/cm25 1.2 A (1)4.4.1 Curren
23、t and voltage fluctuation should be no morethan 65%.A65 % current fluctuation represents a currentdensity fluctuation of about 65 % which, for samples under 15cm2total surface area, is less than or equal to one-half thecurrent density shift due to sample shrinkage over 4 h.Potentiostatic control is
24、not necessary, but may be helpful fordetermining optimum current density when setting up proce-dures for a new alloy.4.5 Membrane FilterMust be solvent and electrolyte re-sistant, with pore size of 0.4 to 0.8 m. Filters made ofpoly(vinyl chloride) (fibrous) or polycarbonate (nonfibrous)meet these re
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