ASTM C177 Thermal Conductivity Test

ASTM C177 is a standard test method for steady-state heat flux measurements and thermal transmission properties using the guarded-hot-plate apparatus. This test method is used to determine the thermal conductivity of solid materials, such as ceramics, metals, plastics, and composites, under steady-state conditions.

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Introduction

The measurement of thermal conductivity has become a critical need in industries that deal in material science, engineering, and construction. The thermal conductivity of any material is essentially a property that tells about its potential to conduct heat, and this property finds commendable application in various fields such as insulation, electronics, and thermal management systems. The test method for measuring materials, according to ASTM C177, involves the guarded hot plate apparatus. It also boasts excellent accuracy and reliability, making it a critical technique for testing thermal properties in all materials, from insulation to metals.

Scope

ASTM C177 describes the measurement of thermal transmission properties by the guarded hot plate method for flat, homogeneous specimens in thicknesses from 1 up to 50 mm. Materials to be tested may include, but are not limited to, insulations, polymers, metals, ceramics, and composites. This test primarily yields results that are the thermal conductivity of the material, W/m·K. The standard applies to materials for which the thermal conductivities range from 0.02 to 200 W/m·K, encompassing low-conductivity insulating materials through high-conductivity metals.

ASTM C177 Test Procedure

The ASTM C177 test method employs a guarded hot plate apparatus. Further, using the specimen’s aggregate thickness and the degree to which their temperatures vary, this thermal conductivity test calculates the rate at which heat moves through the samples.

For the test to produce reliable findings, the specimens must be as equal in terms of shape, thickness, and density as feasible. Furthermore, variations in the similarity and homogeneity of the specimens can interfere with the heat flow, changing the temperatures that different thermocouples and measuring equipment read.

We place specimens on opposite sides of a hot-plate device guarded for the test. We use guard heaters, or auxiliary heaters, to minimize lateral heat transfer from the hot plate (the central heater) and to direct the heat flow through the specimens arranged in parallel with the hot plate between them.

The power provided to the hot plate is equivalent to the total amount of heat delivered to the specimens. When the temperature and voltage readings stabilize, we reach equilibrium.

Thermal conductivity is calculated using the equation k=P/[t*(Tm- Ta)]. In this equation, P stands for power, t for the thickness of the combined specimens, Tm for the temperature of the central heater, and Ta for the temperature of the auxiliary heater.

ASTM C177 Test Specimens

The following are some of the test specimen details of the test:

Particulars	Details
Sample details	Flat and curved are acceptable.
Sample dimension	3 mm to 50 mm thickness
Sample preparation	The sample is prepared cautiously with uniform thickness and does not have any surface irregularities. The sample also needs to be free of contaminants .

Data

Data requirements include:

Temperatures of the hot and cold plates.
Heat flow rate.
Specimen dimensions (thickness and area).
Calibration data for the apparatus.
Any corrections applied for heat losses.

Applications of ASTM C177

ASTM C177 is widely used across various industries, including:

Electronics
Automotive and Aerospace
Energy and Utilities

Conclusion

The ASTM C177 thermal conductivity test is a reliable and accurate method for determining the thermal properties of a wide range of materials. Its ability to provide precise measurements under controlled conditions makes it invaluable in research and industrial applications. By understanding the thermal conductivity of materials, engineers and scientists can make informed decisions about material selection, ensuring optimal performance in their respective applications. ASTM C177 provides the foundational data needed to innovate and improve material performance, whether for insulating homes or managing heat in electronic devices. Also learn about, ASTM C518 Steady-State Thermal Transmission Properties

Why Choose Infinita Lab for ASTM C177?

Infinita Lab is a trusted USA-based testing laboratory offering ASTM C177 testing services across an extensive network of accredited facilities across the USA.

Infinita Lab is built to serve the full spectrum of modern testing needs—across industries, materials, and methodologies. Our advanced equipment and expert professionals deliver highly accurate and prompt test results, helping businesses achieve quality compliance and product reliability.

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FAQs

What is ASTM C117?

ASTM C117 standard test method for materials finer than 75-um (No. 200) sieve in mineral aggregates by washing.

What is the use of ASTM standards?

Many industries use ASTM Standards because they provide the best possible guidance or scenarios for handling different materials or products.

What is ASTM C127 used for?

The ASTM C127 standard helps to guarantee that aggregates used in building projects are suitable for the intended application by offering exact measurement and preparation processes.

What is the difference between ASTM C177 and ASTM C518?

In ASTM C177 testing, the heat flow, metered section, heat flux, and density are calculated. In ASTM C518, thermal transmittance and thermal conductivity are calculated.