ASTM E785-81(2024)

Standard Specification for Crucibles, Ignition, Laboratory, Metal

ABSTRACT
This specification covers two types of metal ignition crucibles, nickel or platinum, complete with covers, for laboratory use. Two types of crucibles shall be classified according to their capacities: Type I is nickel with capacities of 100 mL and 250 mL and Type II is platinum with capacity of 20 mL. Type I are crucibles and covers which shall be made from 99.4% nickel, spun and hardened and Type II are crucibles and covers which shall be made from 99.9% platinum plus iridium, with the iridium content of not more than 0.4%. The crucibles shall have a standard shape with a flat base to give a firm and stable resting surface. The side wall shall form a sloping and convex surface extending up to the brim. Crucibles shall be of one-piece construction. Covers shall be flat, sunken in the center, and shall have an extension to serve as a handle. The sunken area in the center shall fit inside the crucible.
SCOPE
1.1 This specification covers two types of metal ignition crucibles, nickel or platinum, complete with covers, for laboratory use.

General Information

• Status: Published
• Publication Date: 31-Jan-2024
• ICS: 71.040.20 - Laboratory ware and related apparatus
• Technical Committee: E41 - Laboratory Apparatus
• Drafting Committee: E41.01 - Laboratory Ware and Supplies

Relations

• Replaces: ASTM E785-81(2017) - Standard Specification for Crucibles, Ignition, Laboratory, Metal
• Effective Date: 01-Feb-2024

Overview

ASTM E785-81(2024) – Standard Specification for Crucibles, Ignition, Laboratory, Metal sets forth the requirements for two types of metal laboratory crucibles used in ignition processes: nickel and platinum. Developed by ASTM International, this specification ensures quality, uniformity, and reliability for laboratory crucibles and their matching covers, focusing on material integrity and dimensional precision. The standard is recognized internationally and is suitable for laboratory, industrial, and government procurement contexts.

Key Topics

1. Crucible Types and Materials

• Type I: Nickel Crucibles
  • Produced using 99.4% nickel, spun and hardened according to ASTM B162.
  • Available capacities: 100 mL and 250 mL.
• Type II: Platinum Crucibles
  • Made from 99.9% platinum with up to 0.4% iridium.
  • Single capacity: 20 mL.

2. Design and Construction

• Both types feature a standard laboratory crucible shape with a flat base for stability.
• The side wall is sloping and convex, extending to the brim for uniform heat distribution.
• One-piece construction avoids potential weak points.
• Covers are designed to be flat, sunken in the center, and include an integral handle for ease of use; the sunken area fits inside the crucible for secure coverage.

3. Physical and Dimensional Requirements

• Strict tolerances ensure consistent quality across batches.
• Dimensions such as height, diameter, wall thickness, and total weight are specified for each type and capacity.

4. Quality and Inspection

• Visual and dimensional inspection to ensure freedom from scratches, dents, discoloration, oil, grease, or other contamination.
• Packaging, marking, and acceptance testing are defined for civil, commercial, and military procurement.

Applications

ASTM E785-81 Crucibles serve essential roles in laboratories where accurate, high-temperature ignition and ashing processes are required. Typical uses include:

• Chemical analysis: Accurately measuring residue after sample combustion or treatment.
• Materials testing: Performing loss-on-ignition and other high-temperature tests.
• Quality control: Supporting precise measurement in industrial, pharmaceutical, and academic laboratories.
• Research and development: Enabling rigorous experimentation involving heat treatment of small samples.

Due to their high purity materials and strict manufacturing controls, these crucibles are trusted for critical applications needing contamination-free results.

Related Standards

• ASTM B162: Specification for Nickel Plate, Sheet, and Strip - foundational for Type I crucible material.
• Federal Standard No. 123: Guidelines on marking for shipment (civil agencies).
• MIL-STD-105: Sampling procedures and tables for inspection by attributes.
• MIL-STD-129 and MIL-STD-1188: Marking and packaging for military and commercial supplies.

Practical Value

Conformance with ASTM E785-81(2024) ensures laboratories receive crucibles that meet strict physical and chemical requirements, reducing variability and improving reliability in high-temperature procedures. The use of high-purity nickel and platinum materials, precise tolerances, and explicit inspection protocols make this standard an essential reference for laboratory procurement, auditors, and quality managers. By adhering to this standard, users achieve consistent results and facilitate compliance with both international and governmental standards.

Keywords: ASTM E785, laboratory crucibles, ignition crucible, nickel crucibles, platinum crucibles, laboratory apparatus standard, metal crucibles, laboratory ignition, materials testing, laboratory equipment specification.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E785 − 81 (Reapproved 2024)
Standard Specification for
Crucibles, Ignition, Laboratory, Metal
This standard is issued under the fixed designation E785; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 3.1.1 Type I—Nickel.
Capacity: 100 mL
1.1 This specification covers two types of metal ignition
250 mL
crucibles, nickel or platinum, complete with covers, for labo-
3.1.2 Type II—Platinum.
ratory use.
Capacity: 20 mL
1.2 This international standard was developed in accor-
4. Materials
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4.1 Type I—Crucibles and covers shall be made from
Development of International Standards, Guides and Recom-
99.4 % nickel, spun and hardened in conformance with Speci-
mendations issued by the World Trade Organization Technical
fication B162.
Barriers to Trade (TBT) Committee.
4.2 Type II—Crucibles and covers shall be made from
99.9 % platinum plus iridium, with the iridium content of not
2. Referenced Documents
more than 0.4 %.
2.1 ASTM Standards:
B162 Specification for Nickel Plate, Sheet, and Strip 5. Physical Requirements
2.2 Federal Standards:
5.1 Crucibles shall have a standard shape with a flat base to
Fed. Std. No. 123 Marking for Shipment (Civil Agencies)
give a firm and stable resting surface. The side wall shall form
2.3 Military Standards: a sloping and convex surface extending up to the brim.
MIL-STD-105 Sampling Procedures and Tables for Inspec- Crucibles shall be of one-piece construction.
tion by Attributes
5.2 Covers shall be flat, sunken in the center, and shall have
MIL-STD-129 Marking for Shipment and Storage
an extension to serve as a handle. The sunken area in the center
MIL-STD-1188 Commercial Packaging of Supplies and
shall fit inside the crucible.
Equipment
6. Dimensions, Mass, and Permissible Variations
3. Classification
6.1 Type I crucibles and covers shall conform to the require-
3.1 Types and Capacities—The crucibles shall be furnished
ments of Table 1.
in one or more of the following types or capacities as specified
6.2 Type II Crucibles and Covers:
(see S2.1).
6.2.1 Type II crucibles shall conform to the requirements of
Table 2.
6.2.2 Type II covers shall conform to the requirements of
This specification is under the jurisdiction of ASTM Committee E41 on
Table 3.
Laboratory Apparatus and is the direct responsibility of Subcommittee E41.01 on
Laboratory Ware and Supplies.
7. Workmanship
Current edition approved Feb. 1, 2024. Published February 2024. Originally
approved in 1981. Last previous edition approved in 2017 as E785 – 81 (2017).
7.1 Crucibles and covers shall be free of defects (scratches,
DOI: 10.1520/E0785-81R24.
dents, discolorations) or contamination (grease, oil, foreign
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM matter) that detract from their appearance or that impair their
Standards volume information, refer to the standard’s Document Summary page on
serviceability.
the ASTM website.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
8. Keywords
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
www.dodssp.daps.mil.
8.1 crucibles; ignition; nickel; platinum
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E785 − 81 (2024)
TABLE 1 Crucible Dimensions (Type I)
A
Wall
A OD Exclusive A B A
Capacity, Outside
Bottom OD , Length incl. Inside Diameter of Wall Thickness,
B
Height, mm Thickness , of
mm Handle, mm Sunken Section, mm mm
mL Diameter, mm
mm Handle, mm
100 60 30 64 0.625 67 92 58 0.625
250 83 50 83 0.625 92 116 83 0.625
A
Tolerance ± 2 mm.
B
Tolerance ± 0.25 mm.
TABLE 2 Crucible Dimensions (Type II)
Capacity, Top Inside Bottom Inside Thickness of Thickness of
Height, mm Weight, g
mL Diameter, mm Diameter, mm Side, mm Bottom, mm
20 32.4 ± 0.8 19 ± 1.0 34.5 ± 2.0 0.22 ± 0.05 0.25 ± 0.05 16 ± 1.0
TABLE 3 Cover Requirements (Type II)
Outside Diameter
Length Including Diameter of Sun- Depth of Sunken
Thickness, mm Excluding Handle, Weight, g
Handle, mm ken Section, mm Section, mm
mm
0.137 ± 0.01 36.4 ± 0.2 47 ± 0.5 31.5 ± 0.5 3.0 ± 0.3
SUPPLEMENTARY REQUIREMENTS
The following supplementary requirements are binding when this specification is used by the
Department of Defense and the Federal Government for the procurement of platinum evaporating
dishes.
S1. Sampling S2.3.1.2 Crucibles, not otherwise indexed. Motor volume
minimum weight 24 000 lb.
S1.1 Sampling for nondestructive examination shall be
S2.3.2 Type II–Platinum. Not taken by freight. Ship via UPS
conducted in accordance with MIL-STD-105.
or parcel post.
S2. Ordering Information
S3. Lotting and Sampling
S2.1 Procurement documents should s
...