Editor's Note
This editor’s note highlights the key facts and market implications behind “Piezoelectric Materials – The Most Common Unknow”, with emphasis on sourcing, product fit, fabrication, logistics, or buyer impact.
STONERIDGE Stoneridge (SRI), listed on the New York Stock Exchange, has seen its stock value increase by more than 30% over the past year at the time of writing this report. While Stoneridge's revenues took a significant hit during the peak of the coronavirus, 2021 saw a recovery of approximately 20% to $770 million. Stoneridge employs more than 5,000 people and operates out of Michigan.
What are Piezoelectric Materials?
Piezoelectric materials allow us to harness kinetic energy by converting force into an electrical charge. Piezoelectricity was first defined by the Curie brothers in 1880 and has become a fundamental principle exploited in modern technology. Piezoelectricity refers to a material's ability to produce an electrical charge when subjected to mechanical pressure. This electrical charge is produced by forced asymmetry. In piezoelectric materials, positive and negative charges are separated from each other, maintaining alignment in a symmetrical pattern. When mechanical pressure is applied to the material, this symmetry is lost, resulting in the production of an electrical charge. Beta PVDF Phase. Another unique property of materials is the random nature and presence of Weiss domains (magnetic orientation without external magnetic influence).
It was later discovered that these same materials exhibited a direct reverse property of the piezoelectric effect. It was found that if an electrical charge is applied to the material, repeated mechanical deformation will occur within the material. This discovery gave such materials significant utility, essentially doubling the expected use cases.
Manufacturers and Innovators
Before delving into real-world use case examples, here are three leading companies leveraging piezoelectric materials across a variety of products integrated into modern electronics.
It is worth noting that analysts at Barron's currently list each of the following stocks as "Overweight" or "Buy".
(SRI) Methode Electronics (MEI) Methode Electronics Inc., listed on the New York Stock Exchange, has seen its stock value increase by approximately 15% over the past year at the time of writing this report. Over the past four years, Methode Electronics has managed to continue increasing its revenues by between 4% and 2.36% annually. For 2022, revenues exceeded $1.36 billion.
Methode Electronics employs more than 7,000 people and operates out of Illinois. Kimball Electronics Inc. (KE) Kimball Electronics Inc., listed on the NASDAQ, has seen its stock value increase by more than 32% over the past year at the time of writing this report. While the aforementioned companies struggled from 2019 to 2020, Kimball Electronics was able to boast consistently increasing revenues. With a total of $1.35 billion for 2022, this represents an increase of 4.47% over 2021. Kimball Electronics employs more than 7,000 people and operates out of Indiana.
Recent Developments
Traditionally, naturally occurring piezoelectric materials were used to demonstrate the effect. Most often, the chosen material was quartz. When the limits of natural materials were reached, man-made ceramics became the common choice. Designed in 1952, one of the most common types of piezoelectric ceramics today is still PZT (Lead Zirconate Titanate). However, with drawbacks such as limited deformation, brittleness, and high mass density, PZT is not ideal for all applications. In 1964, PVDF (Polyvinylidene Fluoride) was developed. PVDF has a semi-crystalline structure and generates charges several times larger than quartz. Although this man-made polymer addressed many of PZT's flaws, it had several of its own—such as piezoelectric breakdown at high temperatures and degradation. With recent technological advances and increased demand, PZT and PVDF may have reached their limits.
In the early 2000s, institutes such as GAIKER-IK4 began developing what are known as amorphous piezoelectric polymers. By using an amorphous structure, the material can withstand much higher temperatures. Since piezoelectric effects do not depend on a crystalline structure that degrades at higher temperatures, amorphous structures create a more robust polymer. These amorphous polymers are advanced because they provide higher levels of deformation, significantly reduced weight, and greater rigidity. By achieving this, the field of material applications now allows for the integration of aerospace and electronic devices. With the development of new amorphous piezoelectric polymers and films, failure during use will occur at temperatures up to approximately 150°C or more. Material degradation will occur at around 400°C. While this may limit their use in harsh conditions, the vast majority of applications fall within a suitable range. Like many new materials, these polymers are developed using PVDF and PVT as bases, attempting to maintain the positive features of each material while removing as many flaws as possible. Although these products are newer polymers, they are designed according to current business models. By using an amorphous structure, extensive testing must be conducted on optimal glass transition temperatures. This value is directly related to the strength of the piezoelectric properties the material will possess. The amorphous structure illustrates and relies on short-range order to produce a piezoelectric effect rather than the long-range order seen in crystalline structures. Additionally, many choose to incorporate polyimides into the material structure due to their mechanical, insulating, and thermal properties, as polyimides ensure polarization of molecules regardless of their position.
Use Cases
Previous and current applications of piezoelectric materials include many non-obvious items such as lighters, quartz watches, and even engine management systems. Their most common current use would be in sensors and actuators. While suitable piezoelectric materials have been applied for these use cases, future applications require a more versatile material. Fortunately, the development of piezoelectric polymers is versatile. With ongoing advances in our understanding of materials science and their ability to exhibit direct reverse effects, the number of applications they can be used in continues to grow. Some interesting current and future applications include: Portable and Wearable Electronics
Source: Read the original article | Published: February 02, 2023