ASTM C690 Standard Test Method for Particle Size Distribution of Alumina or Quartz Powders by Electrical Sensing Zone Technique
What is ASTM C690?
ASTM C690 is a standard test method for determining the particle size distribution of alumina or quartz powders using an electrical sensing zone particle size analyzer. It measures particle characteristics as they pass through a small hole in the electrolyte suspension. Each particle produces an electrical pulse whose amplitude relates to the particle volume. Engineers use these measurements to determine particle size distribution within the method’s 0.6 to 56.0 μm range. The method is suitable for material specification, manufacturing control, development, research, and comparison of alumina or quartz powder.
Get Certified ASTM C690 Testing for Reliable Particle Size Distribution Evaluation
The ASTM C690 method provides quantitative particle size distribution information for alumina and quartz powders. The powder is spread in an electrolyte, and a sample suspension is introduced into an electrical sensing zone analyzer. Expert operators monitor the concentration of particles and ensure they are evenly distributed in the suspension for measurement. Analysts process the electrical pulses generated as particles pass through the aperture to determine particle size distribution and related statistical parameters.
What is the scope of ASTM C690?
ASTM C690 specifies methods for determining particle size distribution of alumina or quartz powders ranging from 0.6 to 56.0 μm by an electrical sensing zone particle size analyzer. The analyzer counts individual particles as they pass through an aperture and sends out electric pulses proportional to the particle volume. The method helps sellers and purchasers evaluate powder particle size for material specifications, manufacturing control, development, and research.
Applications: Powder specifications, manufacturing control, quality evaluation, research, development, and comparison of alumina and quartz powders.
What are the uses of ASTM C690 testing?
ASTM C690 testing helps manufacturers and laboratories characterize the particle size distribution of alumina and quartz powders. The results provide useful information for controlling powder quality and comparing material batches. This standard-
Determines the particle size distribution of alumina and quartz powders.
Assists with material specifications and acceptance testing evaluation.
Supports research and development of ceramic raw materials.
Helps compare particle size characteristics between powder lots.
Provides statistical particle-size information for material evaluation.
Supports communication between powder suppliers and purchasers.
Which Materials Can Be Tested Under ASTM C690?
ASTM C690 applies only to alumina and quartz powders within the method’s particle-size range. These powders are prepared as dilute, well-dispersed suspensions in an electrolyte prior to analysis. Skilled personnel should prevent agglomeration and maintain a representative particle suspension because incomplete dispersion can distort the measured distribution.
Why is ASTM C690 important?
ASTM C690 defines a standard electrical sensing zone method for determining the particle size distribution of alumina and quartz powders. Particle size affects powder handling, processing, packing, and the characteristics of ceramic materials produced from the powders.
ASTM C690 Equipment and Sample Preparation Guide
ASTM C690 requires an electrical sensing zone particle size analyzer together with an appropriate aperture, sample beaker, dispersing equipment, pipet, wash bottles, and membrane filtration equipment. The method uses an electrolyte and dispersing medium to create a suitable particle suspension. Technicians should prepare clean, filtered liquids and disperse the powder without breaking particles.
Analysts use representative alumina or quartz powder samples within the 0.6 to 56.0 μm measurement range.
Sample Preparation
Technicians disperse the powder in electrolyte using suitable mixing equipment and transfer a representative aliquot to the sample beaker.
Specimen Dimension
No fixed specimen dimensions apply because the test analyzes powder particles suspended in an electrolyte. The selected aperture and sample concentration determine the measurement configuration.
Instrumentation
Electrical sensing zone particle size analyzer, selected aperture tube, sample beaker, blender or mixer, pipet, wash bottles, membrane filtering device, balance, and suitable laboratory glassware.
Testing Procedures and Requirements for ASTM C690
ASTM C690 analyzes a carefully dispersed, dilute powder suspension in an electrolyte. As individual particles go through the restricting aperture, an electrical pulse is created, and the analyzer determines the particle-size information from the pulse response. The complete procedure for ASTM C690 is given below:
Apparatus Preparation and Aperture and Calibration
Skilled personnel clean the analyzer, sample-contact surfaces, sample beaker, and related equipment before testing. Analysts select an appropriate aperture and calibrate the aperture/electrolyte combination according to the instrument requirements.
Electrolyte Preparation and Sample Dispersion
Technicians prepare filtered electrolyte and dispersing media suitable for the electrical sensing zone measurement. Skilled personnel disperse the alumina or quartz powder in the electrolyte using a blender or equivalent mixer while avoiding conditions that could alter particle size.
Sample Transfer and Suspension Control
Analysts transfer a representative aliquot of the dispersed suspension into the sample beaker containing filtered electrolyte and dispersing medium. Technicians maintain sufficient stirring to keep the particles uniformly suspended without generating excessive air bubbles.
Particle Measurement and Data Collection
The analyzer forces the suspension through the restricting aperture and records electrical pulses produced by individual particles. Analysts collect particle counts and particle-size measurements over the selected measurement range.
Data Processing and Reporting
Skilled experts calculate or obtain particle size distribution and relevant statistical parameters using the instrument’s analysis system. Technicians record material identification, aperture, calibration information, measurement range, particle-size distribution, and statistical results.
ASTM C690 Testing Process and Data Collection
Technicians first prepare the medium, dispersant, and representative powder sample, disperse the powder, and transfer an appropriate aliquot into the sample beaker. The analyzer draws the suspension through the selected aperture, and the particles create electrical pulses. Skilled personnel maintain a uniform suspension and suitable particle concentration throughout the measurement. Analysts then analyze the particles collected to derive the particle size distribution and statistics like the mean, median, mode, quartiles, and standard deviation.
ASTM C690 Testing Procedure Using Electrical Sensing Zone Particle Size Analyzer
Common Challenges and Troubleshooting
Proper dispersion, representative sampling, aperture selection, calibration, and particle concentration are all important to obtaining accurate results. The technicians should try to avoid agglomeration and excessive mixing, which may alter the original particle size. The analyst should also be able to stir the solution without entrapping air bubbles and keep all surfaces in contact with the sample clean. Skilled personnel should check the aperture, calibration, electrolyte cleanliness, sample concentration, and dispersion procedure. If results show unexpected shifts or poor repeatability.
ASTM C690 Analysis Results and Interpretation
The report contains a summary of the particle size distribution of the tested alumina or quartz powder in the specified measurement range. Engineers use these results to evaluate particle-size characteristics and compare the tested powder with material specifications, manufacturing requirements, or other powder lots.
The laboratory reports particle size in μm and may report distribution data as weight percent, count percent, or volume percent, together with statistical parameters such as mean, median, mode, quartiles, and standard deviation.
Technicians record the particle-size distribution obtained from the electrical sensing zone analyzer together with the selected aperture, measurement range, and relevant sample concentration conditions.
Analysts record powder identification, calibration data, dispersion conditions, and measurement configuration during testing.
Engineers compare the measured particle size distribution and statistical results with applicable material or product requirements to evaluate the tested powder’s particle-size characteristics.
ASTM C690 measures the particle size distribution of alumina or quartz powders using the electrical sensing zone technique.
What particle-size range does ASTM C690 cover?
The technique applies to alumina or quartz powder ranging from 0.6 to 56.0 μm.
Which materials can ASTM C690 test?
ASTM C690 specifically covers alumina and quartz powders.
About Author
Malhar Khole
Malhar Khole is a Material Testing Associate at MaTestLab Inc. and holds a postgraduate degree in Material Science and Technology from IIT (BHU), Varanasi.
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